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ActivityStack.javaAPI DocAndroid 5.1 API186489Thu Mar 12 22:22:42 GMT 2015com.android.server.am

ActivityStack

public final class ActivityStack extends Object
State and management of a single stack of activities.

Fields Summary
static final int
LAUNCH_TICK
static final int
PAUSE_TIMEOUT
static final int
STOP_TIMEOUT
static final int
DESTROY_TIMEOUT
static final long
ACTIVITY_INACTIVE_RESET_TIME
static final long
START_WARN_TIME
static final boolean
SHOW_APP_STARTING_PREVIEW
static final long
TRANSLUCENT_CONVERSION_TIMEOUT
static final boolean
SCREENSHOT_FORCE_565
final ActivityManagerService
mService
final com.android.server.wm.WindowManagerService
mWindowManager
private ArrayList
mTaskHistory
The back history of all previous (and possibly still running) activities. It contains #TaskRecord objects.
final ArrayList
mValidateAppTokens
Used for validating app tokens with window manager.
final ArrayList
mLRUActivities
List of running activities, sorted by recent usage. The first entry in the list is the least recently used. It contains HistoryRecord objects.
final ArrayList
mNoAnimActivities
Animations that for the current transition have requested not to be considered for the transition animation.
ActivityRecord
mPausingActivity
When we are in the process of pausing an activity, before starting the next one, this variable holds the activity that is currently being paused.
ActivityRecord
mLastPausedActivity
This is the last activity that we put into the paused state. This is used to determine if we need to do an activity transition while sleeping, when we normally hold the top activity paused.
ActivityRecord
mLastNoHistoryActivity
Activities that specify No History must be removed once the user navigates away from them. If the device goes to sleep with such an activity in the paused state then we save it here and finish it later if another activity replaces it on wakeup.
ActivityRecord
mResumedActivity
Current activity that is resumed, or null if there is none.
ActivityRecord
mLastStartedActivity
This is the last activity that has been started. It is only used to identify when multiple activities are started at once so that the user can be warned they may not be in the activity they think they are.
ActivityRecord
mTranslucentActivityWaiting
private ArrayList
mUndrawnActivitiesBelowTopTranslucent
boolean
mConfigWillChange
Set when we know we are going to be calling updateConfiguration() soon, so want to skip intermediate config checks.
long
mLaunchStartTime
long
mFullyDrawnStartTime
int
mCurrentUser
final int
mStackId
final com.android.server.am.ActivityStackSupervisor.ActivityContainer
mActivityContainer
ArrayList
mStacks
The other stacks, in order, on the attached display. Updated at attach/detach time.
int
mDisplayId
The attached Display's unique identifier, or -1 if detached
final ActivityStackSupervisor
mStackSupervisor
Run all ActivityStacks through this
static final int
PAUSE_TIMEOUT_MSG
static final int
DESTROY_TIMEOUT_MSG
static final int
LAUNCH_TICK_MSG
static final int
STOP_TIMEOUT_MSG
static final int
DESTROY_ACTIVITIES_MSG
static final int
TRANSLUCENT_TIMEOUT_MSG
static final int
RELEASE_BACKGROUND_RESOURCES_TIMEOUT_MSG
final android.os.Handler
mHandler
static final int
FINISH_IMMEDIATELY
static final int
FINISH_AFTER_PAUSE
static final int
FINISH_AFTER_VISIBLE
Constructors Summary
ActivityStack(com.android.server.am.ActivityStackSupervisor.ActivityContainer activityContainer)

        mActivityContainer = activityContainer;
        mStackSupervisor = activityContainer.getOuter();
        mService = mStackSupervisor.mService;
        mHandler = new ActivityStackHandler(mService.mHandler.getLooper());
        mWindowManager = mService.mWindowManager;
        mStackId = activityContainer.mStackId;
        mCurrentUser = mService.mCurrentUserId;
Methods Summary
final voidactivityDestroyedLocked(android.os.IBinder token, java.lang.String reason)

        final long origId = Binder.clearCallingIdentity();
        try {
            ActivityRecord r = ActivityRecord.forToken(token);
            if (r != null) {
                mHandler.removeMessages(DESTROY_TIMEOUT_MSG, r);
            }
            if (DEBUG_CONTAINERS) Slog.d(TAG, "activityDestroyedLocked: r=" + r);

            if (isInStackLocked(token) != null) {
                if (r.state == ActivityState.DESTROYING) {
                    cleanUpActivityLocked(r, true, false);
                    removeActivityFromHistoryLocked(r, reason);
                }
            }
            mStackSupervisor.resumeTopActivitiesLocked();
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
final voidactivityPausedLocked(android.os.IBinder token, boolean timeout)

        if (DEBUG_PAUSE) Slog.v(
            TAG, "Activity paused: token=" + token + ", timeout=" + timeout);

        final ActivityRecord r = isInStackLocked(token);
        if (r != null) {
            mHandler.removeMessages(PAUSE_TIMEOUT_MSG, r);
            if (mPausingActivity == r) {
                if (DEBUG_STATES) Slog.v(TAG, "Moving to PAUSED: " + r
                        + (timeout ? " (due to timeout)" : " (pause complete)"));
                completePauseLocked(true);
            } else {
                EventLog.writeEvent(EventLogTags.AM_FAILED_TO_PAUSE,
                        r.userId, System.identityHashCode(r), r.shortComponentName,
                        mPausingActivity != null
                            ? mPausingActivity.shortComponentName : "(none)");
            }
        }
final voidactivityStoppedLocked(ActivityRecord r, android.os.Bundle icicle, android.os.PersistableBundle persistentState, java.lang.CharSequence description)

        if (r.state != ActivityState.STOPPING) {
            Slog.i(TAG, "Activity reported stop, but no longer stopping: " + r);
            mHandler.removeMessages(STOP_TIMEOUT_MSG, r);
            return;
        }
        if (persistentState != null) {
            r.persistentState = persistentState;
            mService.notifyTaskPersisterLocked(r.task, false);
        }
        if (DEBUG_SAVED_STATE) Slog.i(TAG, "Saving icicle of " + r + ": " + icicle);
        if (icicle != null) {
            // If icicle is null, this is happening due to a timeout, so we
            // haven't really saved the state.
            r.icicle = icicle;
            r.haveState = true;
            r.launchCount = 0;
            r.updateThumbnailLocked(null, description);
        }
        if (!r.stopped) {
            if (DEBUG_STATES) Slog.v(TAG, "Moving to STOPPED: " + r + " (stop complete)");
            mHandler.removeMessages(STOP_TIMEOUT_MSG, r);
            r.stopped = true;
            r.state = ActivityState.STOPPED;
            if (mActivityContainer.mActivityDisplay.mVisibleBehindActivity == r) {
                mStackSupervisor.requestVisibleBehindLocked(r, false);
            }
            if (r.finishing) {
                r.clearOptionsLocked();
            } else {
                if (r.configDestroy) {
                    destroyActivityLocked(r, true, "stop-config");
                    mStackSupervisor.resumeTopActivitiesLocked();
                } else {
                    mStackSupervisor.updatePreviousProcessLocked(r);
                }
            }
        }
voidaddTask(TaskRecord task, boolean toTop, boolean moving)

        task.stack = this;
        if (toTop) {
            insertTaskAtTop(task);
        } else {
            mTaskHistory.add(0, task);
            updateTaskMovement(task, false);
        }
        if (!moving && task.voiceSession != null) {
            try {
                task.voiceSession.taskStarted(task.intent, task.taskId);
            } catch (RemoteException e) {
            }
        }
private voidadjustFocusedActivityLocked(ActivityRecord r, java.lang.String reason)

        if (mStackSupervisor.isFrontStack(this) && mService.mFocusedActivity == r) {
            ActivityRecord next = topRunningActivityLocked(null);
            if (next != r) {
                final TaskRecord task = r.task;
                if (r.frontOfTask && task == topTask() && task.isOverHomeStack()) {
                    mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo(),
                            reason + " adjustFocus");
                }
            }
            ActivityRecord top = mStackSupervisor.topRunningActivityLocked();
            if (top != null) {
                mService.setFocusedActivityLocked(top, reason + " adjustTopFocus");
            }
        }
voidawakeFromSleepingLocked()

        // Ensure activities are no longer sleeping.
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                activities.get(activityNdx).setSleeping(false);
            }
        }
        if (mPausingActivity != null) {
            Slog.d(TAG, "awakeFromSleepingLocked: previously pausing activity didn't pause");
            activityPausedLocked(mPausingActivity.appToken, true);
        }
final voidbackgroundResourcesReleased()

        mHandler.removeMessages(RELEASE_BACKGROUND_RESOURCES_TIMEOUT_MSG);
        final ActivityRecord r = getVisibleBehindActivity();
        if (r != null) {
            mStackSupervisor.mStoppingActivities.add(r);
            setVisibleBehindActivity(null);
            mStackSupervisor.scheduleIdleTimeoutLocked(null);
        }
        mStackSupervisor.resumeTopActivitiesLocked();
voidcancelInitializingActivities()
If any activities below the top running one are in the INITIALIZING state and they have a starting window displayed then remove that starting window. It is possible that the activity in this state will never resumed in which case that starting window will be orphaned.

        final ActivityRecord topActivity = topRunningActivityLocked(null);
        boolean aboveTop = true;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (aboveTop) {
                    if (r == topActivity) {
                        aboveTop = false;
                    }
                    continue;
                }

                if (r.state == ActivityState.INITIALIZING && r.mStartingWindowShown) {
                    if (DEBUG_VISBILITY) Slog.w(TAG, "Found orphaned starting window " + r);
                    r.mStartingWindowShown = false;
                    mWindowManager.removeAppStartingWindow(r.appToken);
                }
            }
        }
booleancheckReadyForSleepLocked()

return
true if something must be done before going to sleep.

        if (mResumedActivity != null) {
            // Still have something resumed; can't sleep until it is paused.
            if (DEBUG_PAUSE) Slog.v(TAG, "Sleep needs to pause " + mResumedActivity);
            if (DEBUG_USER_LEAVING) Slog.v(TAG, "Sleep => pause with userLeaving=false");
            startPausingLocked(false, true, false, false);
            return true;
        }
        if (mPausingActivity != null) {
            // Still waiting for something to pause; can't sleep yet.
            if (DEBUG_PAUSE) Slog.v(TAG, "Sleep still waiting to pause " + mPausingActivity);
            return true;
        }

        return false;
final voidcleanUpActivityLocked(ActivityRecord r, boolean cleanServices, boolean setState)
Perform the common clean-up of an activity record. This is called both as part of destroyActivityLocked() (when destroying the client-side representation) and cleaning things up as a result of its hosting processing going away, in which case there is no remaining client-side state to destroy so only the cleanup here is needed.

        if (mResumedActivity == r) {
            mResumedActivity = null;
        }
        if (mPausingActivity == r) {
            mPausingActivity = null;
        }
        mService.clearFocusedActivity(r);

        r.configDestroy = false;
        r.frozenBeforeDestroy = false;

        if (setState) {
            if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYED: " + r + " (cleaning up)");
            r.state = ActivityState.DESTROYED;
            if (DEBUG_APP) Slog.v(TAG, "Clearing app during cleanUp for activity " + r);
            r.app = null;
        }

        // Make sure this record is no longer in the pending finishes list.
        // This could happen, for example, if we are trimming activities
        // down to the max limit while they are still waiting to finish.
        mStackSupervisor.mFinishingActivities.remove(r);
        mStackSupervisor.mWaitingVisibleActivities.remove(r);

        // Remove any pending results.
        if (r.finishing && r.pendingResults != null) {
            for (WeakReference<PendingIntentRecord> apr : r.pendingResults) {
                PendingIntentRecord rec = apr.get();
                if (rec != null) {
                    mService.cancelIntentSenderLocked(rec, false);
                }
            }
            r.pendingResults = null;
        }

        if (cleanServices) {
            cleanUpActivityServicesLocked(r);
        }

        // Get rid of any pending idle timeouts.
        removeTimeoutsForActivityLocked(r);
        if (getVisibleBehindActivity() == r) {
            mStackSupervisor.requestVisibleBehindLocked(r, false);
        }
final voidcleanUpActivityServicesLocked(ActivityRecord r)
Perform clean-up of service connections in an activity record.

        // Throw away any services that have been bound by this activity.
        if (r.connections != null) {
            Iterator<ConnectionRecord> it = r.connections.iterator();
            while (it.hasNext()) {
                ConnectionRecord c = it.next();
                mService.mServices.removeConnectionLocked(c, null, r);
            }
            r.connections = null;
        }
voidclearLaunchTime(ActivityRecord r)

        // Make sure that there is no activity waiting for this to launch.
        if (mStackSupervisor.mWaitingActivityLaunched.isEmpty()) {
            r.displayStartTime = r.fullyDrawnStartTime = 0;
        } else {
            mStackSupervisor.removeTimeoutsForActivityLocked(r);
            mStackSupervisor.scheduleIdleTimeoutLocked(r);
        }
voidcloseSystemDialogsLocked()

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if ((r.info.flags&ActivityInfo.FLAG_FINISH_ON_CLOSE_SYSTEM_DIALOGS) != 0) {
                    finishActivityLocked(r, Activity.RESULT_CANCELED, null, "close-sys", true);
                }
            }
        }
private voidcompletePauseLocked(boolean resumeNext)

        ActivityRecord prev = mPausingActivity;
        if (DEBUG_PAUSE) Slog.v(TAG, "Complete pause: " + prev);

        if (prev != null) {
            prev.state = ActivityState.PAUSED;
            if (prev.finishing) {
                if (DEBUG_PAUSE) Slog.v(TAG, "Executing finish of activity: " + prev);
                prev = finishCurrentActivityLocked(prev, FINISH_AFTER_VISIBLE, false);
            } else if (prev.app != null) {
                if (DEBUG_PAUSE) Slog.v(TAG, "Enqueueing pending stop: " + prev);
                if (prev.waitingVisible) {
                    prev.waitingVisible = false;
                    mStackSupervisor.mWaitingVisibleActivities.remove(prev);
                    if (DEBUG_SWITCH || DEBUG_PAUSE) Slog.v(
                            TAG, "Complete pause, no longer waiting: " + prev);
                }
                if (prev.configDestroy) {
                    // The previous is being paused because the configuration
                    // is changing, which means it is actually stopping...
                    // To juggle the fact that we are also starting a new
                    // instance right now, we need to first completely stop
                    // the current instance before starting the new one.
                    if (DEBUG_PAUSE) Slog.v(TAG, "Destroying after pause: " + prev);
                    destroyActivityLocked(prev, true, "pause-config");
                } else if (!hasVisibleBehindActivity()) {
                    // If we were visible then resumeTopActivities will release resources before
                    // stopping.
                    mStackSupervisor.mStoppingActivities.add(prev);
                    if (mStackSupervisor.mStoppingActivities.size() > 3 ||
                            prev.frontOfTask && mTaskHistory.size() <= 1) {
                        // If we already have a few activities waiting to stop,
                        // then give up on things going idle and start clearing
                        // them out. Or if r is the last of activity of the last task the stack
                        // will be empty and must be cleared immediately.
                        if (DEBUG_PAUSE) Slog.v(TAG, "To many pending stops, forcing idle");
                        mStackSupervisor.scheduleIdleLocked();
                    } else {
                        mStackSupervisor.checkReadyForSleepLocked();
                    }
                }
            } else {
                if (DEBUG_PAUSE) Slog.v(TAG, "App died during pause, not stopping: " + prev);
                prev = null;
            }
            mPausingActivity = null;
        }

        if (resumeNext) {
            final ActivityStack topStack = mStackSupervisor.getFocusedStack();
            if (!mService.isSleepingOrShuttingDown()) {
                mStackSupervisor.resumeTopActivitiesLocked(topStack, prev, null);
            } else {
                mStackSupervisor.checkReadyForSleepLocked();
                ActivityRecord top = topStack.topRunningActivityLocked(null);
                if (top == null || (prev != null && top != prev)) {
                    // If there are no more activities available to run,
                    // do resume anyway to start something.  Also if the top
                    // activity on the stack is not the just paused activity,
                    // we need to go ahead and resume it to ensure we complete
                    // an in-flight app switch.
                    mStackSupervisor.resumeTopActivitiesLocked(topStack, null, null);
                }
            }
        }

        if (prev != null) {
            prev.resumeKeyDispatchingLocked();

            if (prev.app != null && prev.cpuTimeAtResume > 0
                    && mService.mBatteryStatsService.isOnBattery()) {
                long diff = mService.mProcessCpuTracker.getCpuTimeForPid(prev.app.pid)
                        - prev.cpuTimeAtResume;
                if (diff > 0) {
                    BatteryStatsImpl bsi = mService.mBatteryStatsService.getActiveStatistics();
                    synchronized (bsi) {
                        BatteryStatsImpl.Uid.Proc ps =
                                bsi.getProcessStatsLocked(prev.info.applicationInfo.uid,
                                        prev.info.packageName);
                        if (ps != null) {
                            ps.addForegroundTimeLocked(diff);
                        }
                    }
                }
            }
            prev.cpuTimeAtResume = 0; // reset it
        }

        // Notfiy when the task stack has changed
        mService.notifyTaskStackChangedLocked();
private voidcompleteResumeLocked(ActivityRecord next)
Once we know that we have asked an application to put an activity in the resumed state (either by launching it or explicitly telling it), this function updates the rest of our state to match that fact.

        next.idle = false;
        next.results = null;
        next.newIntents = null;

        if (next.isHomeActivity() && next.isNotResolverActivity()) {
            ProcessRecord app = next.task.mActivities.get(0).app;
            if (app != null && app != mService.mHomeProcess) {
                mService.mHomeProcess = app;
            }
        }

        if (next.nowVisible) {
            // We won't get a call to reportActivityVisibleLocked() so dismiss lockscreen now.
            mStackSupervisor.notifyActivityDrawnForKeyguard();
        }

        // schedule an idle timeout in case the app doesn't do it for us.
        mStackSupervisor.scheduleIdleTimeoutLocked(next);

        mStackSupervisor.reportResumedActivityLocked(next);

        next.resumeKeyDispatchingLocked();
        mNoAnimActivities.clear();

        // Mark the point when the activity is resuming
        // TODO: To be more accurate, the mark should be before the onCreate,
        //       not after the onResume. But for subsequent starts, onResume is fine.
        if (next.app != null) {
            next.cpuTimeAtResume = mService.mProcessCpuTracker.getCpuTimeForPid(next.app.pid);
        } else {
            next.cpuTimeAtResume = 0; // Couldn't get the cpu time of process
        }

        next.returningOptions = null;

        if (mActivityContainer.mActivityDisplay.mVisibleBehindActivity == next) {
            // When resuming an activity, require it to call requestVisibleBehind() again.
            mActivityContainer.mActivityDisplay.setVisibleBehindActivity(null);
        }
voidconvertToTranslucent(ActivityRecord r)

        mTranslucentActivityWaiting = r;
        mUndrawnActivitiesBelowTopTranslucent.clear();
        mHandler.sendEmptyMessageDelayed(TRANSLUCENT_TIMEOUT_MSG, TRANSLUCENT_CONVERSION_TIMEOUT);
TaskRecordcreateTaskRecord(int taskId, android.content.pm.ActivityInfo info, android.content.Intent intent, android.service.voice.IVoiceInteractionSession voiceSession, com.android.internal.app.IVoiceInteractor voiceInteractor, boolean toTop)

        TaskRecord task = new TaskRecord(mService, taskId, info, intent, voiceSession,
                voiceInteractor);
        addTask(task, toTop, false);
        return task;
final voiddestroyActivitiesLocked(ProcessRecord owner, java.lang.String reason)

        boolean lastIsOpaque = false;
        boolean activityRemoved = false;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (r.finishing) {
                    continue;
                }
                if (r.fullscreen) {
                    lastIsOpaque = true;
                }
                if (owner != null && r.app != owner) {
                    continue;
                }
                if (!lastIsOpaque) {
                    continue;
                }
                if (r.isDestroyable()) {
                    if (DEBUG_SWITCH) Slog.v(TAG, "Destroying " + r + " in state " + r.state
                            + " resumed=" + mResumedActivity
                            + " pausing=" + mPausingActivity + " for reason " + reason);
                    if (destroyActivityLocked(r, true, reason)) {
                        activityRemoved = true;
                    }
                }
            }
        }
        if (activityRemoved) {
            mStackSupervisor.resumeTopActivitiesLocked();
        }
final booleandestroyActivityLocked(ActivityRecord r, boolean removeFromApp, java.lang.String reason)
Destroy the current CLIENT SIDE instance of an activity. This may be called both when actually finishing an activity, or when performing a configuration switch where we destroy the current client-side object but then create a new client-side object for this same HistoryRecord.

        if (DEBUG_SWITCH || DEBUG_CLEANUP) Slog.v(
            TAG, "Removing activity from " + reason + ": token=" + r
              + ", app=" + (r.app != null ? r.app.processName : "(null)"));
        EventLog.writeEvent(EventLogTags.AM_DESTROY_ACTIVITY,
                r.userId, System.identityHashCode(r),
                r.task.taskId, r.shortComponentName, reason);

        boolean removedFromHistory = false;

        cleanUpActivityLocked(r, false, false);

        final boolean hadApp = r.app != null;

        if (hadApp) {
            if (removeFromApp) {
                r.app.activities.remove(r);
                if (mService.mHeavyWeightProcess == r.app && r.app.activities.size() <= 0) {
                    mService.mHeavyWeightProcess = null;
                    mService.mHandler.sendEmptyMessage(
                            ActivityManagerService.CANCEL_HEAVY_NOTIFICATION_MSG);
                }
                if (r.app.activities.isEmpty()) {
                    // Update any services we are bound to that might care about whether
                    // their client may have activities.
                    mService.mServices.updateServiceConnectionActivitiesLocked(r.app);
                    // No longer have activities, so update LRU list and oom adj.
                    mService.updateLruProcessLocked(r.app, false, null);
                    mService.updateOomAdjLocked();
                }
            }

            boolean skipDestroy = false;

            try {
                if (DEBUG_SWITCH) Slog.i(TAG, "Destroying: " + r);
                r.app.thread.scheduleDestroyActivity(r.appToken, r.finishing,
                        r.configChangeFlags);
            } catch (Exception e) {
                // We can just ignore exceptions here...  if the process
                // has crashed, our death notification will clean things
                // up.
                //Slog.w(TAG, "Exception thrown during finish", e);
                if (r.finishing) {
                    removeActivityFromHistoryLocked(r, reason + " exceptionInScheduleDestroy");
                    removedFromHistory = true;
                    skipDestroy = true;
                }
            }

            r.nowVisible = false;

            // If the activity is finishing, we need to wait on removing it
            // from the list to give it a chance to do its cleanup.  During
            // that time it may make calls back with its token so we need to
            // be able to find it on the list and so we don't want to remove
            // it from the list yet.  Otherwise, we can just immediately put
            // it in the destroyed state since we are not removing it from the
            // list.
            if (r.finishing && !skipDestroy) {
                if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYING: " + r
                        + " (destroy requested)");
                r.state = ActivityState.DESTROYING;
                Message msg = mHandler.obtainMessage(DESTROY_TIMEOUT_MSG, r);
                mHandler.sendMessageDelayed(msg, DESTROY_TIMEOUT);
            } else {
                if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYED: " + r + " (destroy skipped)");
                r.state = ActivityState.DESTROYED;
                if (DEBUG_APP) Slog.v(TAG, "Clearing app during destroy for activity " + r);
                r.app = null;
            }
        } else {
            // remove this record from the history.
            if (r.finishing) {
                removeActivityFromHistoryLocked(r, reason + " hadNoApp");
                removedFromHistory = true;
            } else {
                if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYED: " + r + " (no app)");
                r.state = ActivityState.DESTROYED;
                if (DEBUG_APP) Slog.v(TAG, "Clearing app during destroy for activity " + r);
                r.app = null;
            }
        }

        r.configChangeFlags = 0;

        if (!mLRUActivities.remove(r) && hadApp) {
            Slog.w(TAG, "Activity " + r + " being finished, but not in LRU list");
        }

        return removedFromHistory;
booleandumpActivitiesLocked(java.io.FileDescriptor fd, java.io.PrintWriter pw, boolean dumpAll, boolean dumpClient, java.lang.String dumpPackage, boolean needSep, java.lang.String header)

        boolean printed = false;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            printed |= ActivityStackSupervisor.dumpHistoryList(fd, pw,
                    mTaskHistory.get(taskNdx).mActivities, "    ", "Hist", true, !dumpAll,
                    dumpClient, dumpPackage, needSep, header,
                    "    Task id #" + task.taskId);
            if (printed) {
                header = null;
            }
        }
        return printed;
final voidensureActivitiesVisibleLocked(ActivityRecord starting, int configChanges)
Make sure that all activities that need to be visible (that is, they currently can be seen by the user) actually are.

        ActivityRecord top = topRunningActivityLocked(null);
        if (top == null) {
            return;
        }
        if (DEBUG_VISBILITY) Slog.v(
                TAG, "ensureActivitiesVisible behind " + top
                + " configChanges=0x" + Integer.toHexString(configChanges));

        if (mTranslucentActivityWaiting != top) {
            mUndrawnActivitiesBelowTopTranslucent.clear();
            if (mTranslucentActivityWaiting != null) {
                // Call the callback with a timeout indication.
                notifyActivityDrawnLocked(null);
                mTranslucentActivityWaiting = null;
            }
            mHandler.removeMessages(TRANSLUCENT_TIMEOUT_MSG);
        }

        // If the top activity is not fullscreen, then we need to
        // make sure any activities under it are now visible.
        boolean aboveTop = true;
        boolean behindFullscreen = !isStackVisible();

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            final ArrayList<ActivityRecord> activities = task.mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (r.finishing) {
                    continue;
                }
                if (aboveTop && r != top) {
                    continue;
                }
                aboveTop = false;
                // mLaunchingBehind: Activities launching behind are at the back of the task stack
                // but must be drawn initially for the animation as though they were visible.
                if (!behindFullscreen || r.mLaunchTaskBehind) {
                    if (DEBUG_VISBILITY) Slog.v(
                            TAG, "Make visible? " + r + " finishing=" + r.finishing
                            + " state=" + r.state);

                    // First: if this is not the current activity being started, make
                    // sure it matches the current configuration.
                    if (r != starting) {
                        ensureActivityConfigurationLocked(r, 0);
                    }

                    if (r.app == null || r.app.thread == null) {
                        // This activity needs to be visible, but isn't even
                        // running...  get it started, but don't resume it
                        // at this point.
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Start and freeze screen for " + r);
                        if (r != starting) {
                            r.startFreezingScreenLocked(r.app, configChanges);
                        }
                        if (!r.visible || r.mLaunchTaskBehind) {
                            if (DEBUG_VISBILITY) Slog.v(
                                    TAG, "Starting and making visible: " + r);
                            setVisibile(r, true);
                        }
                        if (r != starting) {
                            mStackSupervisor.startSpecificActivityLocked(r, false, false);
                        }

                    } else if (r.visible) {
                        // If this activity is already visible, then there is nothing
                        // else to do here.
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Skipping: already visible at " + r);
                        r.stopFreezingScreenLocked(false);
                        try {
                            if (r.returningOptions != null) {
                                r.app.thread.scheduleOnNewActivityOptions(r.appToken,
                                        r.returningOptions);
                            }
                        } catch(RemoteException e) {
                        }
                    } else {
                        // This activity is not currently visible, but is running.
                        // Tell it to become visible.
                        r.visible = true;
                        if (r.state != ActivityState.RESUMED && r != starting) {
                            // If this activity is paused, tell it
                            // to now show its window.
                            if (DEBUG_VISBILITY) Slog.v(
                                    TAG, "Making visible and scheduling visibility: " + r);
                            try {
                                if (mTranslucentActivityWaiting != null) {
                                    r.updateOptionsLocked(r.returningOptions);
                                    mUndrawnActivitiesBelowTopTranslucent.add(r);
                                }
                                setVisibile(r, true);
                                r.sleeping = false;
                                r.app.pendingUiClean = true;
                                r.app.thread.scheduleWindowVisibility(r.appToken, true);
                                r.stopFreezingScreenLocked(false);
                            } catch (Exception e) {
                                // Just skip on any failure; we'll make it
                                // visible when it next restarts.
                                Slog.w(TAG, "Exception thrown making visibile: "
                                        + r.intent.getComponent(), e);
                            }
                        }
                    }

                    // Aggregate current change flags.
                    configChanges |= r.configChangeFlags;

                    if (r.fullscreen) {
                        // At this point, nothing else needs to be shown
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Fullscreen: at " + r);
                        behindFullscreen = true;
                    } else if (!isHomeStack() && r.frontOfTask && task.isOverHomeStack()) {
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Showing home: at " + r);
                        behindFullscreen = true;
                    }
                } else {
                    if (DEBUG_VISBILITY) Slog.v(
                        TAG, "Make invisible? " + r + " finishing=" + r.finishing
                        + " state=" + r.state
                        + " behindFullscreen=" + behindFullscreen);
                    // Now for any activities that aren't visible to the user, make
                    // sure they no longer are keeping the screen frozen.
                    if (r.visible) {
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Making invisible: " + r);
                        try {
                            setVisibile(r, false);
                            switch (r.state) {
                                case STOPPING:
                                case STOPPED:
                                    if (r.app != null && r.app.thread != null) {
                                        if (DEBUG_VISBILITY) Slog.v(
                                                TAG, "Scheduling invisibility: " + r);
                                        r.app.thread.scheduleWindowVisibility(r.appToken, false);
                                    }
                                    break;

                                case INITIALIZING:
                                case RESUMED:
                                case PAUSING:
                                case PAUSED:
                                    // This case created for transitioning activities from
                                    // translucent to opaque {@link Activity#convertToOpaque}.
                                    if (getVisibleBehindActivity() == r) {
                                        releaseBackgroundResources();
                                    } else {
                                        if (!mStackSupervisor.mStoppingActivities.contains(r)) {
                                            mStackSupervisor.mStoppingActivities.add(r);
                                        }
                                        mStackSupervisor.scheduleIdleLocked();
                                    }
                                    break;

                                default:
                                    break;
                            }
                        } catch (Exception e) {
                            // Just skip on any failure; we'll make it
                            // visible when it next restarts.
                            Slog.w(TAG, "Exception thrown making hidden: "
                                    + r.intent.getComponent(), e);
                        }
                    } else {
                        if (DEBUG_VISBILITY) Slog.v(TAG, "Already invisible: " + r);
                    }
                }
            }
        }

        if (mTranslucentActivityWaiting != null &&
                mUndrawnActivitiesBelowTopTranslucent.isEmpty()) {
            // Nothing is getting drawn or everything was already visible, don't wait for timeout.
            notifyActivityDrawnLocked(null);
        }
final booleanensureActivityConfigurationLocked(ActivityRecord r, int globalChanges)
Make sure the given activity matches the current configuration. Returns false if the activity had to be destroyed. Returns true if the configuration is the same, or the activity will remain running as-is for whatever reason. Ensures the HistoryRecord is updated with the correct configuration and all other bookkeeping is handled.

        if (mConfigWillChange) {
            if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Skipping config check (will change): " + r);
            return true;
        }

        if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                "Ensuring correct configuration: " + r);

        // Short circuit: if the two configurations are the exact same
        // object (the common case), then there is nothing to do.
        Configuration newConfig = mService.mConfiguration;
        if (r.configuration == newConfig && !r.forceNewConfig) {
            if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Configuration unchanged in " + r);
            return true;
        }

        // We don't worry about activities that are finishing.
        if (r.finishing) {
            if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Configuration doesn't matter in finishing " + r);
            r.stopFreezingScreenLocked(false);
            return true;
        }

        // Okay we now are going to make this activity have the new config.
        // But then we need to figure out how it needs to deal with that.
        Configuration oldConfig = r.configuration;
        r.configuration = newConfig;

        // Determine what has changed.  May be nothing, if this is a config
        // that has come back from the app after going idle.  In that case
        // we just want to leave the official config object now in the
        // activity and do nothing else.
        final int changes = oldConfig.diff(newConfig);
        if (changes == 0 && !r.forceNewConfig) {
            if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Configuration no differences in " + r);
            return true;
        }

        // If the activity isn't currently running, just leave the new
        // configuration and it will pick that up next time it starts.
        if (r.app == null || r.app.thread == null) {
            if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                    "Configuration doesn't matter not running " + r);
            r.stopFreezingScreenLocked(false);
            r.forceNewConfig = false;
            return true;
        }

        // Figure out how to handle the changes between the configurations.
        if (DEBUG_SWITCH || DEBUG_CONFIGURATION) {
            Slog.v(TAG, "Checking to restart " + r.info.name + ": changed=0x"
                    + Integer.toHexString(changes) + ", handles=0x"
                    + Integer.toHexString(r.info.getRealConfigChanged())
                    + ", newConfig=" + newConfig);
        }
        if ((changes&(~r.info.getRealConfigChanged())) != 0 || r.forceNewConfig) {
            // Aha, the activity isn't handling the change, so DIE DIE DIE.
            r.configChangeFlags |= changes;
            r.startFreezingScreenLocked(r.app, globalChanges);
            r.forceNewConfig = false;
            if (r.app == null || r.app.thread == null) {
                if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                        "Config is destroying non-running " + r);
                destroyActivityLocked(r, true, "config");
            } else if (r.state == ActivityState.PAUSING) {
                // A little annoying: we are waiting for this activity to
                // finish pausing.  Let's not do anything now, but just
                // flag that it needs to be restarted when done pausing.
                if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                        "Config is skipping already pausing " + r);
                r.configDestroy = true;
                return true;
            } else if (r.state == ActivityState.RESUMED) {
                // Try to optimize this case: the configuration is changing
                // and we need to restart the top, resumed activity.
                // Instead of doing the normal handshaking, just say
                // "restart!".
                if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                        "Config is relaunching resumed " + r);
                relaunchActivityLocked(r, r.configChangeFlags, true);
                r.configChangeFlags = 0;
            } else {
                if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG,
                        "Config is relaunching non-resumed " + r);
                relaunchActivityLocked(r, r.configChangeFlags, false);
                r.configChangeFlags = 0;
            }

            // All done...  tell the caller we weren't able to keep this
            // activity around.
            return false;
        }

        // Default case: the activity can handle this new configuration, so
        // hand it over.  Note that we don't need to give it the new
        // configuration, since we always send configuration changes to all
        // process when they happen so it can just use whatever configuration
        // it last got.
        if (r.app != null && r.app.thread != null) {
            try {
                if (DEBUG_CONFIGURATION) Slog.v(TAG, "Sending new config to " + r);
                r.app.thread.scheduleActivityConfigurationChanged(r.appToken);
            } catch (RemoteException e) {
                // If process died, whatever.
            }
        }
        r.stopFreezingScreenLocked(false);

        return true;
ActivityRecordfindActivityLocked(android.content.Intent intent, android.content.pm.ActivityInfo info)
Returns the first activity (starting from the top of the stack) that is the same as the given activity. Returns null if no such activity is found.

        ComponentName cls = intent.getComponent();
        if (info.targetActivity != null) {
            cls = new ComponentName(info.packageName, info.targetActivity);
        }
        final int userId = UserHandle.getUserId(info.applicationInfo.uid);

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            TaskRecord task = mTaskHistory.get(taskNdx);
            if (!isCurrentProfileLocked(task.userId)) {
                return null;
            }
            final ArrayList<ActivityRecord> activities = task.mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                ActivityRecord r = activities.get(activityNdx);
                if (!r.finishing && r.intent.getComponent().equals(cls) && r.userId == userId) {
                    //Slog.i(TAG, "Found matching class!");
                    //dump();
                    //Slog.i(TAG, "For Intent " + intent + " bringing to top: " + r.intent);
                    return r;
                }
            }
        }

        return null;
ActivityRecordfindNextTranslucentActivity(ActivityRecord r)

        TaskRecord task = r.task;
        if (task == null) {
            return null;
        }

        ActivityStack stack = task.stack;
        if (stack == null) {
            return null;
        }

        int stackNdx = mStacks.indexOf(stack);

        ArrayList<TaskRecord> tasks = stack.mTaskHistory;
        int taskNdx = tasks.indexOf(task);

        ArrayList<ActivityRecord> activities = task.mActivities;
        int activityNdx = activities.indexOf(r) + 1;

        final int numStacks = mStacks.size();
        while (stackNdx < numStacks) {
            tasks = mStacks.get(stackNdx).mTaskHistory;
            final int numTasks = tasks.size();
            while (taskNdx < numTasks) {
                activities = tasks.get(taskNdx).mActivities;
                final int numActivities = activities.size();
                while (activityNdx < numActivities) {
                    final ActivityRecord activity = activities.get(activityNdx);
                    if (!activity.finishing) {
                        return activity.fullscreen ? null : activity;
                    }
                    ++activityNdx;
                }
                activityNdx = 0;
                ++taskNdx;
            }
            taskNdx = 0;
            ++stackNdx;
        }

        return null;
ActivityRecordfindTaskLocked(ActivityRecord target)
Returns the top activity in any existing task matching the given Intent. Returns null if no such task is found.

        Intent intent = target.intent;
        ActivityInfo info = target.info;
        ComponentName cls = intent.getComponent();
        if (info.targetActivity != null) {
            cls = new ComponentName(info.packageName, info.targetActivity);
        }
        final int userId = UserHandle.getUserId(info.applicationInfo.uid);
        boolean isDocument = intent != null & intent.isDocument();
        // If documentData is non-null then it must match the existing task data.
        Uri documentData = isDocument ? intent.getData() : null;

        if (DEBUG_TASKS) Slog.d(TAG, "Looking for task of " + target + " in " + this);
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            if (task.voiceSession != null) {
                // We never match voice sessions; those always run independently.
                if (DEBUG_TASKS) Slog.d(TAG, "Skipping " + task + ": voice session");
                continue;
            }
            if (task.userId != userId) {
                // Looking for a different task.
                if (DEBUG_TASKS) Slog.d(TAG, "Skipping " + task + ": different user");
                continue;
            }
            final ActivityRecord r = task.getTopActivity();
            if (r == null || r.finishing || r.userId != userId ||
                    r.launchMode == ActivityInfo.LAUNCH_SINGLE_INSTANCE) {
                if (DEBUG_TASKS) Slog.d(TAG, "Skipping " + task + ": mismatch root " + r);
                continue;
            }

            final Intent taskIntent = task.intent;
            final Intent affinityIntent = task.affinityIntent;
            final boolean taskIsDocument;
            final Uri taskDocumentData;
            if (taskIntent != null && taskIntent.isDocument()) {
                taskIsDocument = true;
                taskDocumentData = taskIntent.getData();
            } else if (affinityIntent != null && affinityIntent.isDocument()) {
                taskIsDocument = true;
                taskDocumentData = affinityIntent.getData();
            } else {
                taskIsDocument = false;
                taskDocumentData = null;
            }

            if (DEBUG_TASKS) Slog.d(TAG, "Comparing existing cls="
                    + taskIntent.getComponent().flattenToShortString()
                    + "/aff=" + r.task.rootAffinity + " to new cls="
                    + intent.getComponent().flattenToShortString() + "/aff=" + info.taskAffinity);
            if (!isDocument && !taskIsDocument && task.rootAffinity != null) {
                if (task.rootAffinity.equals(target.taskAffinity)) {
                    if (DEBUG_TASKS) Slog.d(TAG, "Found matching affinity!");
                    return r;
                }
            } else if (taskIntent != null && taskIntent.getComponent() != null &&
                    taskIntent.getComponent().compareTo(cls) == 0 &&
                    Objects.equals(documentData, taskDocumentData)) {
                if (DEBUG_TASKS) Slog.d(TAG, "Found matching class!");
                //dump();
                if (DEBUG_TASKS) Slog.d(TAG, "For Intent " + intent + " bringing to top: "
                        + r.intent);
                return r;
            } else if (affinityIntent != null && affinityIntent.getComponent() != null &&
                    affinityIntent.getComponent().compareTo(cls) == 0 &&
                    Objects.equals(documentData, taskDocumentData)) {
                if (DEBUG_TASKS) Slog.d(TAG, "Found matching class!");
                //dump();
                if (DEBUG_TASKS) Slog.d(TAG, "For Intent " + intent + " bringing to top: "
                        + r.intent);
                return r;
            } else if (DEBUG_TASKS) {
                Slog.d(TAG, "Not a match: " + task);
            }
        }

        return null;
final booleanfinishActivityAffinityLocked(ActivityRecord r)

        ArrayList<ActivityRecord> activities = r.task.mActivities;
        for (int index = activities.indexOf(r); index >= 0; --index) {
            ActivityRecord cur = activities.get(index);
            if (!Objects.equals(cur.taskAffinity, r.taskAffinity)) {
                break;
            }
            finishActivityLocked(cur, Activity.RESULT_CANCELED, null, "request-affinity", true);
        }
        return true;
final booleanfinishActivityLocked(ActivityRecord r, int resultCode, android.content.Intent resultData, java.lang.String reason, boolean oomAdj)

return
Returns true if this activity has been removed from the history list, or false if it is still in the list and will be removed later.

        if (r.finishing) {
            Slog.w(TAG, "Duplicate finish request for " + r);
            return false;
        }

        r.makeFinishing();
        final TaskRecord task = r.task;
        EventLog.writeEvent(EventLogTags.AM_FINISH_ACTIVITY,
                r.userId, System.identityHashCode(r),
                task.taskId, r.shortComponentName, reason);
        final ArrayList<ActivityRecord> activities = task.mActivities;
        final int index = activities.indexOf(r);
        if (index < (activities.size() - 1)) {
            task.setFrontOfTask();
            if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET) != 0) {
                // If the caller asked that this activity (and all above it)
                // be cleared when the task is reset, don't lose that information,
                // but propagate it up to the next activity.
                ActivityRecord next = activities.get(index+1);
                next.intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
            }
        }

        r.pauseKeyDispatchingLocked();

        adjustFocusedActivityLocked(r, "finishActivity");

        finishActivityResultsLocked(r, resultCode, resultData);

        if (mResumedActivity == r) {
            boolean endTask = index <= 0;
            if (DEBUG_VISBILITY || DEBUG_TRANSITION) Slog.v(TAG,
                    "Prepare close transition: finishing " + r);
            mWindowManager.prepareAppTransition(endTask
                    ? AppTransition.TRANSIT_TASK_CLOSE
                    : AppTransition.TRANSIT_ACTIVITY_CLOSE, false);

            // Tell window manager to prepare for this one to be removed.
            mWindowManager.setAppVisibility(r.appToken, false);

            if (mPausingActivity == null) {
                if (DEBUG_PAUSE) Slog.v(TAG, "Finish needs to pause: " + r);
                if (DEBUG_USER_LEAVING) Slog.v(TAG, "finish() => pause with userLeaving=false");
                startPausingLocked(false, false, false, false);
            }

            if (endTask) {
                mStackSupervisor.endLockTaskModeIfTaskEnding(task);
            }
        } else if (r.state != ActivityState.PAUSING) {
            // If the activity is PAUSING, we will complete the finish once
            // it is done pausing; else we can just directly finish it here.
            if (DEBUG_PAUSE) Slog.v(TAG, "Finish not pausing: " + r);
            return finishCurrentActivityLocked(r, FINISH_AFTER_PAUSE, oomAdj) == null;
        } else {
            if (DEBUG_PAUSE) Slog.v(TAG, "Finish waiting for pause of: " + r);
        }

        return false;
final voidfinishActivityResultsLocked(ActivityRecord r, int resultCode, android.content.Intent resultData)

        // send the result
        ActivityRecord resultTo = r.resultTo;
        if (resultTo != null) {
            if (DEBUG_RESULTS) Slog.v(TAG, "Adding result to " + resultTo
                    + " who=" + r.resultWho + " req=" + r.requestCode
                    + " res=" + resultCode + " data=" + resultData);
            if (resultTo.userId != r.userId) {
                if (resultData != null) {
                    resultData.setContentUserHint(r.userId);
                }
            }
            if (r.info.applicationInfo.uid > 0) {
                mService.grantUriPermissionFromIntentLocked(r.info.applicationInfo.uid,
                        resultTo.packageName, resultData,
                        resultTo.getUriPermissionsLocked(), resultTo.userId);
            }
            resultTo.addResultLocked(r, r.resultWho, r.requestCode, resultCode,
                                     resultData);
            r.resultTo = null;
        }
        else if (DEBUG_RESULTS) Slog.v(TAG, "No result destination from " + r);

        // Make sure this HistoryRecord is not holding on to other resources,
        // because clients have remote IPC references to this object so we
        // can't assume that will go away and want to avoid circular IPC refs.
        r.results = null;
        r.pendingResults = null;
        r.newIntents = null;
        r.icicle = null;
voidfinishAllActivitiesLocked(boolean immediately)

        boolean noActivitiesInStack = true;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                noActivitiesInStack = false;
                if (r.finishing && !immediately) {
                    continue;
                }
                Slog.d(TAG, "finishAllActivitiesLocked: finishing " + r + " immediately");
                finishCurrentActivityLocked(r, FINISH_IMMEDIATELY, false);
            }
        }
        if (noActivitiesInStack) {
            mActivityContainer.onTaskListEmptyLocked();
        }
final ActivityRecordfinishCurrentActivityLocked(ActivityRecord r, int mode, boolean oomAdj)


            
        // First things first: if this activity is currently visible,
        // and the resumed activity is not yet visible, then hold off on
        // finishing until the resumed one becomes visible.
        if (mode == FINISH_AFTER_VISIBLE && r.nowVisible) {
            if (!mStackSupervisor.mStoppingActivities.contains(r)) {
                mStackSupervisor.mStoppingActivities.add(r);
                if (mStackSupervisor.mStoppingActivities.size() > 3
                        || r.frontOfTask && mTaskHistory.size() <= 1) {
                    // If we already have a few activities waiting to stop,
                    // then give up on things going idle and start clearing
                    // them out. Or if r is the last of activity of the last task the stack
                    // will be empty and must be cleared immediately.
                    mStackSupervisor.scheduleIdleLocked();
                } else {
                    mStackSupervisor.checkReadyForSleepLocked();
                }
            }
            if (DEBUG_STATES) Slog.v(TAG, "Moving to STOPPING: " + r
                    + " (finish requested)");
            r.state = ActivityState.STOPPING;
            if (oomAdj) {
                mService.updateOomAdjLocked();
            }
            return r;
        }

        // make sure the record is cleaned out of other places.
        mStackSupervisor.mStoppingActivities.remove(r);
        mStackSupervisor.mGoingToSleepActivities.remove(r);
        mStackSupervisor.mWaitingVisibleActivities.remove(r);
        if (mResumedActivity == r) {
            mResumedActivity = null;
        }
        final ActivityState prevState = r.state;
        if (DEBUG_STATES) Slog.v(TAG, "Moving to FINISHING: " + r);
        r.state = ActivityState.FINISHING;

        if (mode == FINISH_IMMEDIATELY
                || prevState == ActivityState.STOPPED
                || prevState == ActivityState.INITIALIZING) {
            // If this activity is already stopped, we can just finish
            // it right now.
            r.makeFinishing();
            boolean activityRemoved = destroyActivityLocked(r, true, "finish-imm");
            if (activityRemoved) {
                mStackSupervisor.resumeTopActivitiesLocked();
            }
            if (DEBUG_CONTAINERS) Slog.d(TAG, 
                    "destroyActivityLocked: finishCurrentActivityLocked r=" + r +
                    " destroy returned removed=" + activityRemoved);
            return activityRemoved ? null : r;
        }

        // Need to go through the full pause cycle to get this
        // activity into the stopped state and then finish it.
        if (localLOGV) Slog.v(TAG, "Enqueueing pending finish: " + r);
        mStackSupervisor.mFinishingActivities.add(r);
        r.resumeKeyDispatchingLocked();
        mStackSupervisor.getFocusedStack().resumeTopActivityLocked(null);
        return r;
final voidfinishSubActivityLocked(ActivityRecord self, java.lang.String resultWho, int requestCode)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                ActivityRecord r = activities.get(activityNdx);
                if (r.resultTo == self && r.requestCode == requestCode) {
                    if ((r.resultWho == null && resultWho == null) ||
                        (r.resultWho != null && r.resultWho.equals(resultWho))) {
                        finishActivityLocked(r, Activity.RESULT_CANCELED, null, "request-sub",
                                false);
                    }
                }
            }
        }
        mService.updateOomAdjLocked();
final voidfinishTopRunningActivityLocked(ProcessRecord app)

        ActivityRecord r = topRunningActivityLocked(null);
        if (r != null && r.app == app) {
            // If the top running activity is from this crashing
            // process, then terminate it to avoid getting in a loop.
            Slog.w(TAG, "  Force finishing activity 1 "
                    + r.intent.getComponent().flattenToShortString());
            int taskNdx = mTaskHistory.indexOf(r.task);
            int activityNdx = r.task.mActivities.indexOf(r);
            finishActivityLocked(r, Activity.RESULT_CANCELED, null, "crashed", false);
            // Also terminate any activities below it that aren't yet
            // stopped, to avoid a situation where one will get
            // re-start our crashing activity once it gets resumed again.
            --activityNdx;
            if (activityNdx < 0) {
                do {
                    --taskNdx;
                    if (taskNdx < 0) {
                        break;
                    }
                    activityNdx = mTaskHistory.get(taskNdx).mActivities.size() - 1;
                } while (activityNdx < 0);
            }
            if (activityNdx >= 0) {
                r = mTaskHistory.get(taskNdx).mActivities.get(activityNdx);
                if (r.state == ActivityState.RESUMED
                        || r.state == ActivityState.PAUSING
                        || r.state == ActivityState.PAUSED) {
                    if (!r.isHomeActivity() || mService.mHomeProcess != r.app) {
                        Slog.w(TAG, "  Force finishing activity 2 "
                                + r.intent.getComponent().flattenToShortString());
                        finishActivityLocked(r, Activity.RESULT_CANCELED, null, "crashed", false);
                    }
                }
            }
        }
final voidfinishVoiceTask(android.service.voice.IVoiceInteractionSession session)

        IBinder sessionBinder = session.asBinder();
        boolean didOne = false;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            TaskRecord tr = mTaskHistory.get(taskNdx);
            if (tr.voiceSession != null && tr.voiceSession.asBinder() == sessionBinder) {
                for (int activityNdx = tr.mActivities.size() - 1; activityNdx >= 0; --activityNdx) {
                    ActivityRecord r = tr.mActivities.get(activityNdx);
                    if (!r.finishing) {
                        finishActivityLocked(r, Activity.RESULT_CANCELED, null, "finish-voice",
                                false);
                        didOne = true;
                    }
                }
            }
        }
        if (didOne) {
            mService.updateOomAdjLocked();
        }
booleanforceStopPackageLocked(java.lang.String name, boolean doit, boolean evenPersistent, int userId)

        boolean didSomething = false;
        TaskRecord lastTask = null;
        ComponentName homeActivity = null;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            int numActivities = activities.size();
            for (int activityNdx = 0; activityNdx < numActivities; ++activityNdx) {
                ActivityRecord r = activities.get(activityNdx);
                final boolean samePackage = r.packageName.equals(name)
                        || (name == null && r.userId == userId);
                if ((userId == UserHandle.USER_ALL || r.userId == userId)
                        && (samePackage || r.task == lastTask)
                        && (r.app == null || evenPersistent || !r.app.persistent)) {
                    if (!doit) {
                        if (r.finishing) {
                            // If this activity is just finishing, then it is not
                            // interesting as far as something to stop.
                            continue;
                        }
                        return true;
                    }
                    if (r.isHomeActivity()) {
                        if (homeActivity != null && homeActivity.equals(r.realActivity)) {
                            Slog.i(TAG, "Skip force-stop again " + r);
                            continue;
                        } else {
                            homeActivity = r.realActivity;
                        }
                    }
                    didSomething = true;
                    Slog.i(TAG, "  Force finishing activity 3 " + r);
                    if (samePackage) {
                        if (r.app != null) {
                            r.app.removed = true;
                        }
                        r.app = null;
                    }
                    lastTask = r.task;
                    if (finishActivityLocked(r, Activity.RESULT_CANCELED, null, "force-stop",
                            true)) {
                        // r has been deleted from mActivities, accommodate.
                        --numActivities;
                        --activityNdx;
                    }
                }
            }
        }
        return didSomething;
java.util.ArrayListgetAllTasks()

        return new ArrayList<TaskRecord>(mTaskHistory);
java.util.ArrayListgetDumpActivitiesLocked(java.lang.String name)

        ArrayList<ActivityRecord> activities = new ArrayList<ActivityRecord>();

        if ("all".equals(name)) {
            for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
                activities.addAll(mTaskHistory.get(taskNdx).mActivities);
            }
        } else if ("top".equals(name)) {
            final int top = mTaskHistory.size() - 1;
            if (top >= 0) {
                final ArrayList<ActivityRecord> list = mTaskHistory.get(top).mActivities;
                int listTop = list.size() - 1;
                if (listTop >= 0) {
                    activities.add(list.get(listTop));
                }
            }
        } else {
            ItemMatcher matcher = new ItemMatcher();
            matcher.build(name);

            for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
                for (ActivityRecord r1 : mTaskHistory.get(taskNdx).mActivities) {
                    if (matcher.match(r1, r1.intent.getComponent())) {
                        activities.add(r1);
                    }
                }
            }
        }

        return activities;
public intgetStackId()

        return mStackId;
voidgetTasksLocked(java.util.List list, int callingUid, boolean allowed)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            ActivityRecord r = null;
            ActivityRecord top = null;
            int numActivities = 0;
            int numRunning = 0;
            final ArrayList<ActivityRecord> activities = task.mActivities;
            if (activities.isEmpty()) {
                continue;
            }
            if (!allowed && !task.isHomeTask() && task.effectiveUid != callingUid) {
                continue;
            }
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                r = activities.get(activityNdx);

                // Initialize state for next task if needed.
                if (top == null || (top.state == ActivityState.INITIALIZING)) {
                    top = r;
                    numActivities = numRunning = 0;
                }

                // Add 'r' into the current task.
                numActivities++;
                if (r.app != null && r.app.thread != null) {
                    numRunning++;
                }

                if (localLOGV) Slog.v(
                    TAG, r.intent.getComponent().flattenToShortString()
                    + ": task=" + r.task);
            }

            RunningTaskInfo ci = new RunningTaskInfo();
            ci.id = task.taskId;
            ci.baseActivity = r.intent.getComponent();
            ci.topActivity = top.intent.getComponent();
            ci.lastActiveTime = task.lastActiveTime;

            if (top.task != null) {
                ci.description = top.task.lastDescription;
            }
            ci.numActivities = numActivities;
            ci.numRunning = numRunning;
            //System.out.println(
            //    "#" + maxNum + ": " + " descr=" + ci.description);
            list.add(ci);
        }
ActivityRecordgetVisibleBehindActivity()

        return isAttached() ? mActivityContainer.mActivityDisplay.mVisibleBehindActivity : null;
voidgoToSleep()

        ensureActivitiesVisibleLocked(null, 0);

        // Make sure any stopped but visible activities are now sleeping.
        // This ensures that the activity's onStop() is called.
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (r.state == ActivityState.STOPPING || r.state == ActivityState.STOPPED) {
                    r.setSleeping(true);
                }
            }
        }
voidhandleAppCrashLocked(ProcessRecord app)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (r.app == app) {
                    Slog.w(TAG, "  Force finishing activity 4 "
                            + r.intent.getComponent().flattenToShortString());
                    // Force the destroy to skip right to removal.
                    r.app = null;
                    finishCurrentActivityLocked(r, FINISH_IMMEDIATELY, false);
                }
            }
        }
booleanhandleAppDiedLocked(ProcessRecord app)
Reset local parameters because an app's activity died.

param
app The app of the activity that died.
return
result from removeHistoryRecordsForAppLocked.

        if (mPausingActivity != null && mPausingActivity.app == app) {
            if (DEBUG_PAUSE || DEBUG_CLEANUP) Slog.v(TAG,
                    "App died while pausing: " + mPausingActivity);
            mPausingActivity = null;
        }
        if (mLastPausedActivity != null && mLastPausedActivity.app == app) {
            mLastPausedActivity = null;
            mLastNoHistoryActivity = null;
        }

        return removeHistoryRecordsForAppLocked(app);
booleanhasVisibleBehindActivity()

        return isAttached() && mActivityContainer.mActivityDisplay.hasVisibleBehindActivity();
private voidinsertTaskAtTop(TaskRecord task)

        // If this is being moved to the top by another activity or being launched from the home
        // activity, set mOnTopOfHome accordingly.
        if (isOnHomeDisplay()) {
            ActivityStack lastStack = mStackSupervisor.getLastStack();
            final boolean fromHome = lastStack.isHomeStack();
            if (!isHomeStack() && (fromHome || topTask() != task)) {
                task.setTaskToReturnTo(fromHome
                        ? lastStack.topTask() == null
                                ? HOME_ACTIVITY_TYPE
                                : lastStack.topTask().taskType
                        : APPLICATION_ACTIVITY_TYPE);
            }
        } else {
            task.setTaskToReturnTo(APPLICATION_ACTIVITY_TYPE);
        }

        mTaskHistory.remove(task);
        // Now put task at top.
        int taskNdx = mTaskHistory.size();
        if (!isCurrentProfileLocked(task.userId)) {
            // Put non-current user tasks below current user tasks.
            while (--taskNdx >= 0) {
                if (!isCurrentProfileLocked(mTaskHistory.get(taskNdx).userId)) {
                    break;
                }
            }
            ++taskNdx;
        }
        mTaskHistory.add(taskNdx, task);
        updateTaskMovement(task, true);
final booleanisAttached()

        return mStacks != null;
private booleanisCurrentProfileLocked(int userId)
Checks whether the userid is a profile of the current user.

        if (userId == mCurrentUser) return true;
        for (int i = 0; i < mService.mCurrentProfileIds.length; i++) {
            if (mService.mCurrentProfileIds[i] == userId) return true;
        }
        return false;
final booleanisHomeStack()

        return mStackId == HOME_STACK_ID;
ActivityRecordisInStackLocked(android.os.IBinder token)

        final ActivityRecord r = ActivityRecord.forToken(token);
        if (r != null) {
            final TaskRecord task = r.task;
            if (task != null && task.mActivities.contains(r) && mTaskHistory.contains(task)) {
                if (task.stack != this) Slog.w(TAG,
                    "Illegal state! task does not point to stack it is in.");
                return r;
            }
        }
        return null;
final booleanisOnHomeDisplay()

        return isAttached() &&
                mActivityContainer.mActivityDisplay.mDisplayId == Display.DEFAULT_DISPLAY;
private booleanisStackVisible()

        if (!isAttached()) {
            return false;
        }

        if (mStackSupervisor.isFrontStack(this)) {
            return true;
        }

        /**
         * Start at the task above this one and go up, looking for a visible
         * fullscreen activity, or a translucent activity that requested the
         * wallpaper to be shown behind it.
         */
        for (int i = mStacks.indexOf(this) + 1; i < mStacks.size(); i++) {
            final ArrayList<TaskRecord> tasks = mStacks.get(i).getAllTasks();
            for (int taskNdx = 0; taskNdx < tasks.size(); taskNdx++) {
                final TaskRecord task = tasks.get(taskNdx);
                final ArrayList<ActivityRecord> activities = task.mActivities;
                for (int activityNdx = 0; activityNdx < activities.size(); activityNdx++) {
                    final ActivityRecord r = activities.get(activityNdx);

                    // Conditions for an activity to obscure the stack we're
                    // examining:
                    // 1. Not Finishing AND Visible AND:
                    // 2. Either:
                    // - Full Screen Activity OR
                    // - On top of Home and our stack is NOT home
                    if (!r.finishing && r.visible && (r.fullscreen ||
                            (!isHomeStack() && r.frontOfTask && task.isOverHomeStack()))) {
                        return false;
                    }
                }
            }
        }

        return true;
static final voidlogStartActivity(int tag, ActivityRecord r, TaskRecord task)

        final Uri data = r.intent.getData();
        final String strData = data != null ? data.toSafeString() : null;

        EventLog.writeEvent(tag,
                r.userId, System.identityHashCode(r), task.taskId,
                r.shortComponentName, r.intent.getAction(),
                r.intent.getType(), strData, r.intent.getFlags());
voidminimalResumeActivityLocked(ActivityRecord r)

        r.state = ActivityState.RESUMED;
        if (DEBUG_STATES) Slog.v(TAG, "Moving to RESUMED: " + r
                + " (starting new instance)");
        r.stopped = false;
        mResumedActivity = r;
        r.task.touchActiveTime();
        mService.addRecentTaskLocked(r.task);
        completeResumeLocked(r);
        mStackSupervisor.checkReadyForSleepLocked();
        setLaunchTime(r);
        if (DEBUG_SAVED_STATE) Slog.i(TAG, "Launch completed; removing icicle of " + r.icicle);
voidmoveHomeStackTaskToTop(int homeStackTaskType)

        final int top = mTaskHistory.size() - 1;
        for (int taskNdx = top; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            if (task.taskType == homeStackTaskType) {
                if (DEBUG_TASKS || DEBUG_STACK)
                    Slog.d(TAG, "moveHomeStackTaskToTop: moving " + task);
                mTaskHistory.remove(taskNdx);
                mTaskHistory.add(top, task);
                updateTaskMovement(task, true);
                mWindowManager.moveTaskToTop(task.taskId);
                return;
            }
        }
final booleanmoveTaskToBackLocked(int taskId)
Worker method for rearranging history stack. Implements the function of moving all activities for a specific task (gathering them if disjoint) into a single group at the bottom of the stack. If a watcher is installed, the action is preflighted and the watcher has an opportunity to premeptively cancel the move.

param
taskId The taskId to collect and move to the bottom.
return
Returns true if the move completed, false if not.

        final TaskRecord tr = taskForIdLocked(taskId);
        if (tr == null) {
            Slog.i(TAG, "moveTaskToBack: bad taskId=" + taskId);
            return false;
        }

        Slog.i(TAG, "moveTaskToBack: " + tr);

        mStackSupervisor.endLockTaskModeIfTaskEnding(tr);

        // If we have a watcher, preflight the move before committing to it.  First check
        // for *other* available tasks, but if none are available, then try again allowing the
        // current task to be selected.
        if (mStackSupervisor.isFrontStack(this) && mService.mController != null) {
            ActivityRecord next = topRunningActivityLocked(null, taskId);
            if (next == null) {
                next = topRunningActivityLocked(null, 0);
            }
            if (next != null) {
                // ask watcher if this is allowed
                boolean moveOK = true;
                try {
                    moveOK = mService.mController.activityResuming(next.packageName);
                } catch (RemoteException e) {
                    mService.mController = null;
                    Watchdog.getInstance().setActivityController(null);
                }
                if (!moveOK) {
                    return false;
                }
            }
        }

        if (DEBUG_TRANSITION) Slog.v(TAG,
                "Prepare to back transition: task=" + taskId);

        mTaskHistory.remove(tr);
        mTaskHistory.add(0, tr);
        updateTaskMovement(tr, false);

        // There is an assumption that moving a task to the back moves it behind the home activity.
        // We make sure here that some activity in the stack will launch home.
        int numTasks = mTaskHistory.size();
        for (int taskNdx = numTasks - 1; taskNdx >= 1; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            if (task.isOverHomeStack()) {
                break;
            }
            if (taskNdx == 1) {
                // Set the last task before tr to go to home.
                task.setTaskToReturnTo(HOME_ACTIVITY_TYPE);
            }
        }

        mWindowManager.prepareAppTransition(AppTransition.TRANSIT_TASK_TO_BACK, false);
        mWindowManager.moveTaskToBottom(taskId);

        if (VALIDATE_TOKENS) {
            validateAppTokensLocked();
        }

        final TaskRecord task = mResumedActivity != null ? mResumedActivity.task : null;
        if (task == tr && tr.isOverHomeStack() || numTasks <= 1 && isOnHomeDisplay()) {
            if (!mService.mBooting && !mService.mBooted) {
                // Not ready yet!
                return false;
            }
            final int taskToReturnTo = tr.getTaskToReturnTo();
            tr.setTaskToReturnTo(APPLICATION_ACTIVITY_TYPE);
            return mStackSupervisor.resumeHomeStackTask(taskToReturnTo, null, "moveTaskToBack");
        }

        mStackSupervisor.resumeTopActivitiesLocked();
        return true;
final voidmoveTaskToFrontLocked(TaskRecord tr, ActivityRecord source, android.os.Bundle options, java.lang.String reason)

        if (DEBUG_SWITCH) Slog.v(TAG, "moveTaskToFront: " + tr);

        final int numTasks = mTaskHistory.size();
        final int index = mTaskHistory.indexOf(tr);
        if (numTasks == 0 || index < 0)  {
            // nothing to do!
            if (source != null &&
                    (source.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
                ActivityOptions.abort(options);
            } else {
                updateTransitLocked(AppTransition.TRANSIT_TASK_TO_FRONT, options);
            }
            return;
        }

        // Shift all activities with this task up to the top
        // of the stack, keeping them in the same internal order.
        insertTaskAtTop(tr);
        moveToFront(reason);

        if (DEBUG_TRANSITION) Slog.v(TAG, "Prepare to front transition: task=" + tr);
        if (source != null &&
                (source.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
            mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
            ActivityRecord r = topRunningActivityLocked(null);
            if (r != null) {
                mNoAnimActivities.add(r);
            }
            ActivityOptions.abort(options);
        } else {
            updateTransitLocked(AppTransition.TRANSIT_TASK_TO_FRONT, options);
        }

        mStackSupervisor.resumeTopActivitiesLocked();
        EventLog.writeEvent(EventLogTags.AM_TASK_TO_FRONT, tr.userId, tr.taskId);

        if (VALIDATE_TOKENS) {
            validateAppTokensLocked();
        }
final voidmoveToFront(java.lang.String reason)

        if (isAttached()) {
            if (isOnHomeDisplay()) {
                mStackSupervisor.moveHomeStack(isHomeStack(), reason);
            }
            mStacks.remove(this);
            mStacks.add(this);
            final TaskRecord task = topTask();
            if (task != null) {
                mWindowManager.moveTaskToTop(task.taskId);
            }
        }
final booleannavigateUpToLocked(android.os.IBinder token, android.content.Intent destIntent, int resultCode, android.content.Intent resultData)

        final ActivityRecord srec = ActivityRecord.forToken(token);
        final TaskRecord task = srec.task;
        final ArrayList<ActivityRecord> activities = task.mActivities;
        final int start = activities.indexOf(srec);
        if (!mTaskHistory.contains(task) || (start < 0)) {
            return false;
        }
        int finishTo = start - 1;
        ActivityRecord parent = finishTo < 0 ? null : activities.get(finishTo);
        boolean foundParentInTask = false;
        final ComponentName dest = destIntent.getComponent();
        if (start > 0 && dest != null) {
            for (int i = finishTo; i >= 0; i--) {
                ActivityRecord r = activities.get(i);
                if (r.info.packageName.equals(dest.getPackageName()) &&
                        r.info.name.equals(dest.getClassName())) {
                    finishTo = i;
                    parent = r;
                    foundParentInTask = true;
                    break;
                }
            }
        }

        IActivityController controller = mService.mController;
        if (controller != null) {
            ActivityRecord next = topRunningActivityLocked(srec.appToken, 0);
            if (next != null) {
                // ask watcher if this is allowed
                boolean resumeOK = true;
                try {
                    resumeOK = controller.activityResuming(next.packageName);
                } catch (RemoteException e) {
                    mService.mController = null;
                    Watchdog.getInstance().setActivityController(null);
                }

                if (!resumeOK) {
                    return false;
                }
            }
        }
        final long origId = Binder.clearCallingIdentity();
        for (int i = start; i > finishTo; i--) {
            ActivityRecord r = activities.get(i);
            requestFinishActivityLocked(r.appToken, resultCode, resultData, "navigate-up", true);
            // Only return the supplied result for the first activity finished
            resultCode = Activity.RESULT_CANCELED;
            resultData = null;
        }

        if (parent != null && foundParentInTask) {
            final int parentLaunchMode = parent.info.launchMode;
            final int destIntentFlags = destIntent.getFlags();
            if (parentLaunchMode == ActivityInfo.LAUNCH_SINGLE_INSTANCE ||
                    parentLaunchMode == ActivityInfo.LAUNCH_SINGLE_TASK ||
                    parentLaunchMode == ActivityInfo.LAUNCH_SINGLE_TOP ||
                    (destIntentFlags & Intent.FLAG_ACTIVITY_CLEAR_TOP) != 0) {
                parent.deliverNewIntentLocked(srec.info.applicationInfo.uid, destIntent,
                        srec.packageName);
            } else {
                try {
                    ActivityInfo aInfo = AppGlobals.getPackageManager().getActivityInfo(
                            destIntent.getComponent(), 0, srec.userId);
                    int res = mStackSupervisor.startActivityLocked(srec.app.thread, destIntent,
                            null, aInfo, null, null, parent.appToken, null,
                            0, -1, parent.launchedFromUid, parent.launchedFromPackage,
                            -1, parent.launchedFromUid, 0, null, true, null, null, null);
                    foundParentInTask = res == ActivityManager.START_SUCCESS;
                } catch (RemoteException e) {
                    foundParentInTask = false;
                }
                requestFinishActivityLocked(parent.appToken, resultCode,
                        resultData, "navigate-up", true);
            }
        }
        Binder.restoreCallingIdentity(origId);
        return foundParentInTask;
voidnotifyActivityDrawnLocked(ActivityRecord r)
Called as activities below the top translucent activity are redrawn. When the last one is redrawn notify the top activity by calling {@link Activity#onTranslucentConversionComplete}.

param
r The most recent background activity to be drawn. Or, if r is null then a timeout occurred and the activity will be notified immediately.

        mActivityContainer.setDrawn();
        if ((r == null)
                || (mUndrawnActivitiesBelowTopTranslucent.remove(r) &&
                        mUndrawnActivitiesBelowTopTranslucent.isEmpty())) {
            // The last undrawn activity below the top has just been drawn. If there is an
            // opaque activity at the top, notify it that it can become translucent safely now.
            final ActivityRecord waitingActivity = mTranslucentActivityWaiting;
            mTranslucentActivityWaiting = null;
            mUndrawnActivitiesBelowTopTranslucent.clear();
            mHandler.removeMessages(TRANSLUCENT_TIMEOUT_MSG);

            if (waitingActivity != null) {
                mWindowManager.setWindowOpaque(waitingActivity.appToken, false);
                if (waitingActivity.app != null && waitingActivity.app.thread != null) {
                    try {
                        waitingActivity.app.thread.scheduleTranslucentConversionComplete(
                                waitingActivity.appToken, r != null);
                    } catch (RemoteException e) {
                    }
                }
            }
        }
intnumActivities()

        int count = 0;
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            count += mTaskHistory.get(taskNdx).mActivities.size();
        }
        return count;
booleanokToShowLocked(ActivityRecord r)

        return isCurrentProfileLocked(r.userId)
                || (r.info.flags & ActivityInfo.FLAG_SHOW_ON_LOCK_SCREEN) != 0;
private booleanrelaunchActivityLocked(ActivityRecord r, int changes, boolean andResume)

        List<ResultInfo> results = null;
        List<ReferrerIntent> newIntents = null;
        if (andResume) {
            results = r.results;
            newIntents = r.newIntents;
        }
        if (DEBUG_SWITCH) Slog.v(TAG, "Relaunching: " + r
                + " with results=" + results + " newIntents=" + newIntents
                + " andResume=" + andResume);
        EventLog.writeEvent(andResume ? EventLogTags.AM_RELAUNCH_RESUME_ACTIVITY
                : EventLogTags.AM_RELAUNCH_ACTIVITY, r.userId, System.identityHashCode(r),
                r.task.taskId, r.shortComponentName);

        r.startFreezingScreenLocked(r.app, 0);

        mStackSupervisor.removeChildActivityContainers(r);

        try {
            if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG,
                    (andResume ? "Relaunching to RESUMED " : "Relaunching to PAUSED ")
                    + r);
            r.forceNewConfig = false;
            r.app.thread.scheduleRelaunchActivity(r.appToken, results, newIntents,
                    changes, !andResume, new Configuration(mService.mConfiguration));
            // Note: don't need to call pauseIfSleepingLocked() here, because
            // the caller will only pass in 'andResume' if this activity is
            // currently resumed, which implies we aren't sleeping.
        } catch (RemoteException e) {
            if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG, "Relaunch failed", e);
        }

        if (andResume) {
            r.results = null;
            r.newIntents = null;
            r.state = ActivityState.RESUMED;
        } else {
            mHandler.removeMessages(PAUSE_TIMEOUT_MSG, r);
            r.state = ActivityState.PAUSED;
        }

        return true;
voidreleaseBackgroundResources()

        if (hasVisibleBehindActivity() &&
                !mHandler.hasMessages(RELEASE_BACKGROUND_RESOURCES_TIMEOUT_MSG)) {
            final ActivityRecord r = getVisibleBehindActivity();
            if (r == topRunningActivityLocked(null)) {
                // Don't release the top activity if it has requested to run behind the next
                // activity.
                return;
            }
            if (DEBUG_STATES) Slog.d(TAG, "releaseBackgroundResources activtyDisplay=" +
                    mActivityContainer.mActivityDisplay + " visibleBehind=" + r + " app=" + r.app +
                    " thread=" + r.app.thread);
            if (r != null && r.app != null && r.app.thread != null) {
                try {
                    r.app.thread.scheduleCancelVisibleBehind(r.appToken);
                } catch (RemoteException e) {
                }
                mHandler.sendEmptyMessageDelayed(RELEASE_BACKGROUND_RESOURCES_TIMEOUT_MSG, 500);
            } else {
                Slog.e(TAG, "releaseBackgroundResources: activity " + r + " no longer running");
                backgroundResourcesReleased();
            }
        }
final intreleaseSomeActivitiesLocked(ProcessRecord app, android.util.ArraySet tasks, java.lang.String reason)

        // Iterate over tasks starting at the back (oldest) first.
        if (DEBUG_RELEASE) Slog.d(TAG, "Trying to release some activities in " + app);
        int maxTasks = tasks.size() / 4;
        if (maxTasks < 1) {
            maxTasks = 1;
        }
        int numReleased = 0;
        for (int taskNdx = 0; taskNdx < mTaskHistory.size() && maxTasks > 0; taskNdx++) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            if (!tasks.contains(task)) {
                continue;
            }
            if (DEBUG_RELEASE) Slog.d(TAG, "Looking for activities to release in " + task);
            int curNum = 0;
            final ArrayList<ActivityRecord> activities = task.mActivities;
            for (int actNdx = 0; actNdx < activities.size(); actNdx++) {
                final ActivityRecord activity = activities.get(actNdx);
                if (activity.app == app && activity.isDestroyable()) {
                    if (DEBUG_RELEASE) Slog.v(TAG, "Destroying " + activity
                            + " in state " + activity.state + " resumed=" + mResumedActivity
                            + " pausing=" + mPausingActivity + " for reason " + reason);
                    destroyActivityLocked(activity, true, reason);
                    if (activities.get(actNdx) != activity) {
                        // Was removed from list, back up so we don't miss the next one.
                        actNdx--;
                    }
                    curNum++;
                }
            }
            if (curNum > 0) {
                numReleased += curNum;
                maxTasks--;
                if (mTaskHistory.get(taskNdx) != task) {
                    // The entire task got removed, back up so we don't miss the next one.
                    taskNdx--;
                }
            }
        }
        if (DEBUG_RELEASE) Slog.d(TAG, "Done releasing: did " + numReleased + " activities");
        return numReleased;
private voidremoveActivityFromHistoryLocked(ActivityRecord r, java.lang.String reason)

        mStackSupervisor.removeChildActivityContainers(r);
        finishActivityResultsLocked(r, Activity.RESULT_CANCELED, null);
        r.makeFinishing();
        if (DEBUG_ADD_REMOVE) {
            RuntimeException here = new RuntimeException("here");
            here.fillInStackTrace();
            Slog.i(TAG, "Removing activity " + r + " from stack");
        }
        r.takeFromHistory();
        removeTimeoutsForActivityLocked(r);
        if (DEBUG_STATES) Slog.v(TAG, "Moving to DESTROYED: " + r + " (removed from history)");
        r.state = ActivityState.DESTROYED;
        if (DEBUG_APP) Slog.v(TAG, "Clearing app during remove for activity " + r);
        r.app = null;
        mWindowManager.removeAppToken(r.appToken);
        if (VALIDATE_TOKENS) {
            validateAppTokensLocked();
        }
        final TaskRecord task = r.task;
        if (task != null && task.removeActivity(r)) {
            if (DEBUG_STACK) Slog.i(TAG,
                    "removeActivityFromHistoryLocked: last activity removed from " + this);
            if (mStackSupervisor.isFrontStack(this) && task == topTask() &&
                    task.isOverHomeStack()) {
                mStackSupervisor.moveHomeStackTaskToTop(task.getTaskToReturnTo(), reason);
            }
            removeTask(task, reason);
        }
        cleanUpActivityServicesLocked(r);
        r.removeUriPermissionsLocked();
private voidremoveHistoryRecordsForAppLocked(java.util.ArrayList list, ProcessRecord app, java.lang.String listName)

        int i = list.size();
        if (DEBUG_CLEANUP) Slog.v(
            TAG, "Removing app " + app + " from list " + listName
            + " with " + i + " entries");
        while (i > 0) {
            i--;
            ActivityRecord r = list.get(i);
            if (DEBUG_CLEANUP) Slog.v(TAG, "Record #" + i + " " + r);
            if (r.app == app) {
                if (DEBUG_CLEANUP) Slog.v(TAG, "---> REMOVING this entry!");
                list.remove(i);
                removeTimeoutsForActivityLocked(r);
            }
        }
booleanremoveHistoryRecordsForAppLocked(ProcessRecord app)

        removeHistoryRecordsForAppLocked(mLRUActivities, app, "mLRUActivities");
        removeHistoryRecordsForAppLocked(mStackSupervisor.mStoppingActivities, app,
                "mStoppingActivities");
        removeHistoryRecordsForAppLocked(mStackSupervisor.mGoingToSleepActivities, app,
                "mGoingToSleepActivities");
        removeHistoryRecordsForAppLocked(mStackSupervisor.mWaitingVisibleActivities, app,
                "mWaitingVisibleActivities");
        removeHistoryRecordsForAppLocked(mStackSupervisor.mFinishingActivities, app,
                "mFinishingActivities");

        boolean hasVisibleActivities = false;

        // Clean out the history list.
        int i = numActivities();
        if (DEBUG_CLEANUP) Slog.v(
            TAG, "Removing app " + app + " from history with " + i + " entries");
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                --i;
                if (DEBUG_CLEANUP) Slog.v(
                    TAG, "Record #" + i + " " + r + ": app=" + r.app);
                if (r.app == app) {
                    boolean remove;
                    if ((!r.haveState && !r.stateNotNeeded) || r.finishing) {
                        // Don't currently have state for the activity, or
                        // it is finishing -- always remove it.
                        remove = true;
                    } else if (r.launchCount > 2 &&
                            r.lastLaunchTime > (SystemClock.uptimeMillis()-60000)) {
                        // We have launched this activity too many times since it was
                        // able to run, so give up and remove it.
                        remove = true;
                    } else {
                        // The process may be gone, but the activity lives on!
                        remove = false;
                    }
                    if (remove) {
                        if (DEBUG_ADD_REMOVE || DEBUG_CLEANUP) {
                            RuntimeException here = new RuntimeException("here");
                            here.fillInStackTrace();
                            Slog.i(TAG, "Removing activity " + r + " from stack at " + i
                                    + ": haveState=" + r.haveState
                                    + " stateNotNeeded=" + r.stateNotNeeded
                                    + " finishing=" + r.finishing
                                    + " state=" + r.state, here);
                        }
                        if (!r.finishing) {
                            Slog.w(TAG, "Force removing " + r + ": app died, no saved state");
                            EventLog.writeEvent(EventLogTags.AM_FINISH_ACTIVITY,
                                    r.userId, System.identityHashCode(r),
                                    r.task.taskId, r.shortComponentName,
                                    "proc died without state saved");
                            if (r.state == ActivityState.RESUMED) {
                                mService.updateUsageStats(r, false);
                            }
                        }
                        removeActivityFromHistoryLocked(r, "appDied");

                    } else {
                        // We have the current state for this activity, so
                        // it can be restarted later when needed.
                        if (localLOGV) Slog.v(
                            TAG, "Keeping entry, setting app to null");
                        if (r.visible) {
                            hasVisibleActivities = true;
                        }
                        if (DEBUG_APP) Slog.v(TAG, "Clearing app during removeHistory for activity "
                                + r);
                        r.app = null;
                        r.nowVisible = false;
                        if (!r.haveState) {
                            if (DEBUG_SAVED_STATE) Slog.i(TAG,
                                    "App died, clearing saved state of " + r);
                            r.icicle = null;
                        }
                    }

                    cleanUpActivityLocked(r, true, true);
                }
            }
        }

        return hasVisibleActivities;
voidremoveTask(TaskRecord task, java.lang.String reason)

        mStackSupervisor.endLockTaskModeIfTaskEnding(task);
        mWindowManager.removeTask(task.taskId);
        final ActivityRecord r = mResumedActivity;
        if (r != null && r.task == task) {
            mResumedActivity = null;
        }

        final int taskNdx = mTaskHistory.indexOf(task);
        final int topTaskNdx = mTaskHistory.size() - 1;
        if (task.isOverHomeStack() && taskNdx < topTaskNdx) {
            final TaskRecord nextTask = mTaskHistory.get(taskNdx + 1);
            if (!nextTask.isOverHomeStack()) {
                nextTask.setTaskToReturnTo(HOME_ACTIVITY_TYPE);
            }
        }
        mTaskHistory.remove(task);
        updateTaskMovement(task, true);

        if (task.mActivities.isEmpty()) {
            final boolean isVoiceSession = task.voiceSession != null;
            if (isVoiceSession) {
                try {
                    task.voiceSession.taskFinished(task.intent, task.taskId);
                } catch (RemoteException e) {
                }
            }
            if (task.autoRemoveFromRecents() || isVoiceSession) {
                // Task creator asked to remove this when done, or this task was a voice
                // interaction, so it should not remain on the recent tasks list.
                mService.mRecentTasks.remove(task);
                task.removedFromRecents();
            }
        }

        if (mTaskHistory.isEmpty()) {
            if (DEBUG_STACK) Slog.i(TAG, "removeTask: moving to back stack=" + this);
            if (isOnHomeDisplay()) {
                mStackSupervisor.moveHomeStack(!isHomeStack(), reason + " leftTaskHistoryEmpty");
            }
            if (mStacks != null) {
                mStacks.remove(this);
                mStacks.add(0, this);
            }
            mActivityContainer.onTaskListEmptyLocked();
        }
private voidremoveTimeoutsForActivityLocked(ActivityRecord r)

        mStackSupervisor.removeTimeoutsForActivityLocked(r);
        mHandler.removeMessages(PAUSE_TIMEOUT_MSG, r);
        mHandler.removeMessages(STOP_TIMEOUT_MSG, r);
        mHandler.removeMessages(DESTROY_TIMEOUT_MSG, r);
        r.finishLaunchTickingLocked();
final booleanrequestFinishActivityLocked(android.os.IBinder token, int resultCode, android.content.Intent resultData, java.lang.String reason, boolean oomAdj)

return
Returns true if the activity is being finished, false if for some reason it is being left as-is.

        ActivityRecord r = isInStackLocked(token);
        if (DEBUG_RESULTS || DEBUG_STATES) Slog.v(
                TAG, "Finishing activity token=" + token + " r="
                + ", result=" + resultCode + ", data=" + resultData
                + ", reason=" + reason);
        if (r == null) {
            return false;
        }

        finishActivityLocked(r, resultCode, resultData, reason, oomAdj);
        return true;
private intresetAffinityTaskIfNeededLocked(TaskRecord affinityTask, TaskRecord task, boolean topTaskIsHigher, boolean forceReset, int taskInsertionPoint)
Helper method for #resetTaskIfNeededLocked. Processes all of the activities in a given TaskRecord looking for an affinity with the task of resetTaskIfNeededLocked.taskTop.

param
affinityTask The task we are looking for an affinity to.
param
task Task that resetTaskIfNeededLocked.taskTop belongs to.
param
topTaskIsHigher True if #task has already been processed by resetTaskIfNeededLocked.
param
forceReset Flag passed in to resetTaskIfNeededLocked.

        int replyChainEnd = -1;
        final int taskId = task.taskId;
        final String taskAffinity = task.affinity;

        final ArrayList<ActivityRecord> activities = affinityTask.mActivities;
        final int numActivities = activities.size();
        final int rootActivityNdx = affinityTask.findEffectiveRootIndex();

        // Do not operate on or below the effective root Activity.
        for (int i = numActivities - 1; i > rootActivityNdx; --i) {
            ActivityRecord target = activities.get(i);
            if (target.frontOfTask)
                break;

            final int flags = target.info.flags;
            boolean finishOnTaskLaunch = (flags & ActivityInfo.FLAG_FINISH_ON_TASK_LAUNCH) != 0;
            boolean allowTaskReparenting = (flags & ActivityInfo.FLAG_ALLOW_TASK_REPARENTING) != 0;

            if (target.resultTo != null) {
                // If this activity is sending a reply to a previous
                // activity, we can't do anything with it now until
                // we reach the start of the reply chain.
                // XXX note that we are assuming the result is always
                // to the previous activity, which is almost always
                // the case but we really shouldn't count on.
                if (replyChainEnd < 0) {
                    replyChainEnd = i;
                }
            } else if (topTaskIsHigher
                    && allowTaskReparenting
                    && taskAffinity != null
                    && taskAffinity.equals(target.taskAffinity)) {
                // This activity has an affinity for our task. Either remove it if we are
                // clearing or move it over to our task.  Note that
                // we currently punt on the case where we are resetting a
                // task that is not at the top but who has activities above
                // with an affinity to it...  this is really not a normal
                // case, and we will need to later pull that task to the front
                // and usually at that point we will do the reset and pick
                // up those remaining activities.  (This only happens if
                // someone starts an activity in a new task from an activity
                // in a task that is not currently on top.)
                if (forceReset || finishOnTaskLaunch) {
                    final int start = replyChainEnd >= 0 ? replyChainEnd : i;
                    if (DEBUG_TASKS) Slog.v(TAG, "Finishing task at index " + start + " to " + i);
                    for (int srcPos = start; srcPos >= i; --srcPos) {
                        final ActivityRecord p = activities.get(srcPos);
                        if (p.finishing) {
                            continue;
                        }
                        finishActivityLocked(p, Activity.RESULT_CANCELED, null, "reset", false);
                    }
                } else {
                    if (taskInsertionPoint < 0) {
                        taskInsertionPoint = task.mActivities.size();

                    }

                    final int start = replyChainEnd >= 0 ? replyChainEnd : i;
                    if (DEBUG_TASKS) Slog.v(TAG, "Reparenting from task=" + affinityTask + ":"
                            + start + "-" + i + " to task=" + task + ":" + taskInsertionPoint);
                    for (int srcPos = start; srcPos >= i; --srcPos) {
                        final ActivityRecord p = activities.get(srcPos);
                        p.setTask(task, null);
                        task.addActivityAtIndex(taskInsertionPoint, p);

                        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Removing and adding activity " + p
                                + " to stack at " + task,
                                new RuntimeException("here").fillInStackTrace());
                        if (DEBUG_TASKS) Slog.v(TAG, "Pulling activity " + p + " from " + srcPos
                                + " in to resetting task " + task);
                        mWindowManager.setAppGroupId(p.appToken, taskId);
                    }
                    mWindowManager.moveTaskToTop(taskId);
                    if (VALIDATE_TOKENS) {
                        validateAppTokensLocked();
                    }

                    // Now we've moved it in to place...  but what if this is
                    // a singleTop activity and we have put it on top of another
                    // instance of the same activity?  Then we drop the instance
                    // below so it remains singleTop.
                    if (target.info.launchMode == ActivityInfo.LAUNCH_SINGLE_TOP) {
                        ArrayList<ActivityRecord> taskActivities = task.mActivities;
                        int targetNdx = taskActivities.indexOf(target);
                        if (targetNdx > 0) {
                            ActivityRecord p = taskActivities.get(targetNdx - 1);
                            if (p.intent.getComponent().equals(target.intent.getComponent())) {
                                finishActivityLocked(p, Activity.RESULT_CANCELED, null, "replace",
                                        false);
                            }
                        }
                    }
                }

                replyChainEnd = -1;
            }
        }
        return taskInsertionPoint;
final android.app.ActivityOptionsresetTargetTaskIfNeededLocked(TaskRecord task, boolean forceReset)
Helper method for #resetTaskIfNeededLocked. We are inside of the task being reset... we'll either finish this activity, push it out for another task, or leave it as-is.

param
task The task containing the Activity (taskTop) that might be reset.
param
forceReset
return
An ActivityOptions that needs to be processed.

        ActivityOptions topOptions = null;

        int replyChainEnd = -1;
        boolean canMoveOptions = true;

        // We only do this for activities that are not the root of the task (since if we finish
        // the root, we may no longer have the task!).
        final ArrayList<ActivityRecord> activities = task.mActivities;
        final int numActivities = activities.size();
        final int rootActivityNdx = task.findEffectiveRootIndex();
        for (int i = numActivities - 1; i > rootActivityNdx; --i ) {
            ActivityRecord target = activities.get(i);
            if (target.frontOfTask)
                break;

            final int flags = target.info.flags;
            final boolean finishOnTaskLaunch =
                    (flags & ActivityInfo.FLAG_FINISH_ON_TASK_LAUNCH) != 0;
            final boolean allowTaskReparenting =
                    (flags & ActivityInfo.FLAG_ALLOW_TASK_REPARENTING) != 0;
            final boolean clearWhenTaskReset =
                    (target.intent.getFlags() & Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET) != 0;

            if (!finishOnTaskLaunch
                    && !clearWhenTaskReset
                    && target.resultTo != null) {
                // If this activity is sending a reply to a previous
                // activity, we can't do anything with it now until
                // we reach the start of the reply chain.
                // XXX note that we are assuming the result is always
                // to the previous activity, which is almost always
                // the case but we really shouldn't count on.
                if (replyChainEnd < 0) {
                    replyChainEnd = i;
                }
            } else if (!finishOnTaskLaunch
                    && !clearWhenTaskReset
                    && allowTaskReparenting
                    && target.taskAffinity != null
                    && !target.taskAffinity.equals(task.affinity)) {
                // If this activity has an affinity for another
                // task, then we need to move it out of here.  We will
                // move it as far out of the way as possible, to the
                // bottom of the activity stack.  This also keeps it
                // correctly ordered with any activities we previously
                // moved.
                final TaskRecord targetTask;
                final ActivityRecord bottom =
                        !mTaskHistory.isEmpty() && !mTaskHistory.get(0).mActivities.isEmpty() ?
                                mTaskHistory.get(0).mActivities.get(0) : null;
                if (bottom != null && target.taskAffinity != null
                        && target.taskAffinity.equals(bottom.task.affinity)) {
                    // If the activity currently at the bottom has the
                    // same task affinity as the one we are moving,
                    // then merge it into the same task.
                    targetTask = bottom.task;
                    if (DEBUG_TASKS) Slog.v(TAG, "Start pushing activity " + target
                            + " out to bottom task " + bottom.task);
                } else {
                    targetTask = createTaskRecord(mStackSupervisor.getNextTaskId(), target.info,
                            null, null, null, false);
                    targetTask.affinityIntent = target.intent;
                    if (DEBUG_TASKS) Slog.v(TAG, "Start pushing activity " + target
                            + " out to new task " + target.task);
                }

                final int targetTaskId = targetTask.taskId;
                mWindowManager.setAppGroupId(target.appToken, targetTaskId);

                boolean noOptions = canMoveOptions;
                final int start = replyChainEnd < 0 ? i : replyChainEnd;
                for (int srcPos = start; srcPos >= i; --srcPos) {
                    final ActivityRecord p = activities.get(srcPos);
                    if (p.finishing) {
                        continue;
                    }

                    canMoveOptions = false;
                    if (noOptions && topOptions == null) {
                        topOptions = p.takeOptionsLocked();
                        if (topOptions != null) {
                            noOptions = false;
                        }
                    }
                    if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Removing activity " + p + " from task="
                            + task + " adding to task=" + targetTask
                            + " Callers=" + Debug.getCallers(4));
                    if (DEBUG_TASKS) Slog.v(TAG, "Pushing next activity " + p
                            + " out to target's task " + target.task);
                    p.setTask(targetTask, null);
                    targetTask.addActivityAtBottom(p);

                    mWindowManager.setAppGroupId(p.appToken, targetTaskId);
                }

                mWindowManager.moveTaskToBottom(targetTaskId);
                if (VALIDATE_TOKENS) {
                    validateAppTokensLocked();
                }

                replyChainEnd = -1;
            } else if (forceReset || finishOnTaskLaunch || clearWhenTaskReset) {
                // If the activity should just be removed -- either
                // because it asks for it, or the task should be
                // cleared -- then finish it and anything that is
                // part of its reply chain.
                int end;
                if (clearWhenTaskReset) {
                    // In this case, we want to finish this activity
                    // and everything above it, so be sneaky and pretend
                    // like these are all in the reply chain.
                    end = numActivities - 1;
                } else if (replyChainEnd < 0) {
                    end = i;
                } else {
                    end = replyChainEnd;
                }
                boolean noOptions = canMoveOptions;
                for (int srcPos = i; srcPos <= end; srcPos++) {
                    ActivityRecord p = activities.get(srcPos);
                    if (p.finishing) {
                        continue;
                    }
                    canMoveOptions = false;
                    if (noOptions && topOptions == null) {
                        topOptions = p.takeOptionsLocked();
                        if (topOptions != null) {
                            noOptions = false;
                        }
                    }
                    if (DEBUG_TASKS) Slog.w(TAG,
                            "resetTaskIntendedTask: calling finishActivity on " + p);
                    if (finishActivityLocked(p, Activity.RESULT_CANCELED, null, "reset", false)) {
                        end--;
                        srcPos--;
                    }
                }
                replyChainEnd = -1;
            } else {
                // If we were in the middle of a chain, well the
                // activity that started it all doesn't want anything
                // special, so leave it all as-is.
                replyChainEnd = -1;
            }
        }

        return topOptions;
final ActivityRecordresetTaskIfNeededLocked(ActivityRecord taskTop, ActivityRecord newActivity)

        boolean forceReset =
                (newActivity.info.flags & ActivityInfo.FLAG_CLEAR_TASK_ON_LAUNCH) != 0;
        if (ACTIVITY_INACTIVE_RESET_TIME > 0
                && taskTop.task.getInactiveDuration() > ACTIVITY_INACTIVE_RESET_TIME) {
            if ((newActivity.info.flags & ActivityInfo.FLAG_ALWAYS_RETAIN_TASK_STATE) == 0) {
                forceReset = true;
            }
        }

        final TaskRecord task = taskTop.task;

        /** False until we evaluate the TaskRecord associated with taskTop. Switches to true
         * for remaining tasks. Used for later tasks to reparent to task. */
        boolean taskFound = false;

        /** If ActivityOptions are moved out and need to be aborted or moved to taskTop. */
        ActivityOptions topOptions = null;

        // Preserve the location for reparenting in the new task.
        int reparentInsertionPoint = -1;

        for (int i = mTaskHistory.size() - 1; i >= 0; --i) {
            final TaskRecord targetTask = mTaskHistory.get(i);

            if (targetTask == task) {
                topOptions = resetTargetTaskIfNeededLocked(task, forceReset);
                taskFound = true;
            } else {
                reparentInsertionPoint = resetAffinityTaskIfNeededLocked(targetTask, task,
                        taskFound, forceReset, reparentInsertionPoint);
            }
        }

        int taskNdx = mTaskHistory.indexOf(task);
        do {
            taskTop = mTaskHistory.get(taskNdx--).getTopActivity();
        } while (taskTop == null && taskNdx >= 0);

        if (topOptions != null) {
            // If we got some ActivityOptions from an activity on top that
            // was removed from the task, propagate them to the new real top.
            if (taskTop != null) {
                taskTop.updateOptionsLocked(topOptions);
            } else {
                topOptions.abort();
            }
        }

        return taskTop;
ActivityRecordrestartPackage(java.lang.String packageName)

        ActivityRecord starting = topRunningActivityLocked(null);

        // All activities that came from the package must be
        // restarted as if there was a config change.
        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord a = activities.get(activityNdx);
                if (a.info.packageName.equals(packageName)) {
                    a.forceNewConfig = true;
                    if (starting != null && a == starting && a.visible) {
                        a.startFreezingScreenLocked(starting.app,
                                ActivityInfo.CONFIG_SCREEN_LAYOUT);
                    }
                }
            }
        }

        return starting;
final booleanresumeTopActivityInnerLocked(ActivityRecord prev, android.os.Bundle options)

        if (ActivityManagerService.DEBUG_LOCKSCREEN) mService.logLockScreen("");

        if (!mService.mBooting && !mService.mBooted) {
            // Not ready yet!
            return false;
        }

        ActivityRecord parent = mActivityContainer.mParentActivity;
        if ((parent != null && parent.state != ActivityState.RESUMED) ||
                !mActivityContainer.isAttachedLocked()) {
            // Do not resume this stack if its parent is not resumed.
            // TODO: If in a loop, make sure that parent stack resumeTopActivity is called 1st.
            return false;
        }

        cancelInitializingActivities();

        // Find the first activity that is not finishing.
        final ActivityRecord next = topRunningActivityLocked(null);

        // Remember how we'll process this pause/resume situation, and ensure
        // that the state is reset however we wind up proceeding.
        final boolean userLeaving = mStackSupervisor.mUserLeaving;
        mStackSupervisor.mUserLeaving = false;

        final TaskRecord prevTask = prev != null ? prev.task : null;
        if (next == null) {
            // There are no more activities!  Let's just start up the
            // Launcher...
            ActivityOptions.abort(options);
            if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: No more activities go home");
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            // Only resume home if on home display
            final int returnTaskType = prevTask == null || !prevTask.isOverHomeStack() ?
                    HOME_ACTIVITY_TYPE : prevTask.getTaskToReturnTo();
            return isOnHomeDisplay() &&
                    mStackSupervisor.resumeHomeStackTask(returnTaskType, prev, "noMoreActivities");
        }

        next.delayedResume = false;

        // If the top activity is the resumed one, nothing to do.
        if (mResumedActivity == next && next.state == ActivityState.RESUMED &&
                    mStackSupervisor.allResumedActivitiesComplete()) {
            // Make sure we have executed any pending transitions, since there
            // should be nothing left to do at this point.
            mWindowManager.executeAppTransition();
            mNoAnimActivities.clear();
            ActivityOptions.abort(options);
            if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: Top activity resumed " + next);
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            return false;
        }

        final TaskRecord nextTask = next.task;
        if (prevTask != null && prevTask.stack == this &&
                prevTask.isOverHomeStack() && prev.finishing && prev.frontOfTask) {
            if (DEBUG_STACK)  mStackSupervisor.validateTopActivitiesLocked();
            if (prevTask == nextTask) {
                prevTask.setFrontOfTask();
            } else if (prevTask != topTask()) {
                // This task is going away but it was supposed to return to the home stack.
                // Now the task above it has to return to the home task instead.
                final int taskNdx = mTaskHistory.indexOf(prevTask) + 1;
                mTaskHistory.get(taskNdx).setTaskToReturnTo(HOME_ACTIVITY_TYPE);
            } else if (!isOnHomeDisplay()) {
                return false;
            } else if (!isHomeStack()){
                if (DEBUG_STATES) Slog.d(TAG,
                        "resumeTopActivityLocked: Launching home next");
                final int returnTaskType = prevTask == null || !prevTask.isOverHomeStack() ?
                        HOME_ACTIVITY_TYPE : prevTask.getTaskToReturnTo();
                return mStackSupervisor.resumeHomeStackTask(returnTaskType, prev, "prevFinished");
            }
        }

        // If we are sleeping, and there is no resumed activity, and the top
        // activity is paused, well that is the state we want.
        if (mService.isSleepingOrShuttingDown()
                && mLastPausedActivity == next
                && mStackSupervisor.allPausedActivitiesComplete()) {
            // Make sure we have executed any pending transitions, since there
            // should be nothing left to do at this point.
            mWindowManager.executeAppTransition();
            mNoAnimActivities.clear();
            ActivityOptions.abort(options);
            if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: Going to sleep and all paused");
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            return false;
        }

        // Make sure that the user who owns this activity is started.  If not,
        // we will just leave it as is because someone should be bringing
        // another user's activities to the top of the stack.
        if (mService.mStartedUsers.get(next.userId) == null) {
            Slog.w(TAG, "Skipping resume of top activity " + next
                    + ": user " + next.userId + " is stopped");
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            return false;
        }

        // The activity may be waiting for stop, but that is no longer
        // appropriate for it.
        mStackSupervisor.mStoppingActivities.remove(next);
        mStackSupervisor.mGoingToSleepActivities.remove(next);
        next.sleeping = false;
        mStackSupervisor.mWaitingVisibleActivities.remove(next);

        if (DEBUG_SWITCH) Slog.v(TAG, "Resuming " + next);

        // If we are currently pausing an activity, then don't do anything
        // until that is done.
        if (!mStackSupervisor.allPausedActivitiesComplete()) {
            if (DEBUG_SWITCH || DEBUG_PAUSE || DEBUG_STATES) Slog.v(TAG,
                    "resumeTopActivityLocked: Skip resume: some activity pausing.");
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            return false;
        }

        // Okay we are now going to start a switch, to 'next'.  We may first
        // have to pause the current activity, but this is an important point
        // where we have decided to go to 'next' so keep track of that.
        // XXX "App Redirected" dialog is getting too many false positives
        // at this point, so turn off for now.
        if (false) {
            if (mLastStartedActivity != null && !mLastStartedActivity.finishing) {
                long now = SystemClock.uptimeMillis();
                final boolean inTime = mLastStartedActivity.startTime != 0
                        && (mLastStartedActivity.startTime + START_WARN_TIME) >= now;
                final int lastUid = mLastStartedActivity.info.applicationInfo.uid;
                final int nextUid = next.info.applicationInfo.uid;
                if (inTime && lastUid != nextUid
                        && lastUid != next.launchedFromUid
                        && mService.checkPermission(
                                android.Manifest.permission.STOP_APP_SWITCHES,
                                -1, next.launchedFromUid)
                        != PackageManager.PERMISSION_GRANTED) {
                    mService.showLaunchWarningLocked(mLastStartedActivity, next);
                } else {
                    next.startTime = now;
                    mLastStartedActivity = next;
                }
            } else {
                next.startTime = SystemClock.uptimeMillis();
                mLastStartedActivity = next;
            }
        }

        // We need to start pausing the current activity so the top one
        // can be resumed...
        boolean dontWaitForPause = (next.info.flags&ActivityInfo.FLAG_RESUME_WHILE_PAUSING) != 0;
        boolean pausing = mStackSupervisor.pauseBackStacks(userLeaving, true, dontWaitForPause);
        if (mResumedActivity != null) {
            if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: Pausing " + mResumedActivity);
            pausing |= startPausingLocked(userLeaving, false, true, dontWaitForPause);
        }
        if (pausing) {
            if (DEBUG_SWITCH || DEBUG_STATES) Slog.v(TAG,
                    "resumeTopActivityLocked: Skip resume: need to start pausing");
            // At this point we want to put the upcoming activity's process
            // at the top of the LRU list, since we know we will be needing it
            // very soon and it would be a waste to let it get killed if it
            // happens to be sitting towards the end.
            if (next.app != null && next.app.thread != null) {
                mService.updateLruProcessLocked(next.app, true, null);
            }
            if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
            return true;
        }

        // If the most recent activity was noHistory but was only stopped rather
        // than stopped+finished because the device went to sleep, we need to make
        // sure to finish it as we're making a new activity topmost.
        if (mService.isSleeping() && mLastNoHistoryActivity != null &&
                !mLastNoHistoryActivity.finishing) {
            if (DEBUG_STATES) Slog.d(TAG, "no-history finish of " + mLastNoHistoryActivity +
                    " on new resume");
            requestFinishActivityLocked(mLastNoHistoryActivity.appToken, Activity.RESULT_CANCELED,
                    null, "no-history", false);
            mLastNoHistoryActivity = null;
        }

        if (prev != null && prev != next) {
            if (!prev.waitingVisible && next != null && !next.nowVisible) {
                prev.waitingVisible = true;
                mStackSupervisor.mWaitingVisibleActivities.add(prev);
                if (DEBUG_SWITCH) Slog.v(
                        TAG, "Resuming top, waiting visible to hide: " + prev);
            } else {
                // The next activity is already visible, so hide the previous
                // activity's windows right now so we can show the new one ASAP.
                // We only do this if the previous is finishing, which should mean
                // it is on top of the one being resumed so hiding it quickly
                // is good.  Otherwise, we want to do the normal route of allowing
                // the resumed activity to be shown so we can decide if the
                // previous should actually be hidden depending on whether the
                // new one is found to be full-screen or not.
                if (prev.finishing) {
                    mWindowManager.setAppVisibility(prev.appToken, false);
                    if (DEBUG_SWITCH) Slog.v(TAG, "Not waiting for visible to hide: "
                            + prev + ", waitingVisible="
                            + (prev != null ? prev.waitingVisible : null)
                            + ", nowVisible=" + next.nowVisible);
                } else {
                    if (DEBUG_SWITCH) Slog.v(TAG, "Previous already visible but still waiting to hide: "
                        + prev + ", waitingVisible="
                        + (prev != null ? prev.waitingVisible : null)
                        + ", nowVisible=" + next.nowVisible);
                }
            }
        }

        // Launching this app's activity, make sure the app is no longer
        // considered stopped.
        try {
            AppGlobals.getPackageManager().setPackageStoppedState(
                    next.packageName, false, next.userId); /* TODO: Verify if correct userid */
        } catch (RemoteException e1) {
        } catch (IllegalArgumentException e) {
            Slog.w(TAG, "Failed trying to unstop package "
                    + next.packageName + ": " + e);
        }

        // We are starting up the next activity, so tell the window manager
        // that the previous one will be hidden soon.  This way it can know
        // to ignore it when computing the desired screen orientation.
        boolean anim = true;
        if (prev != null) {
            if (prev.finishing) {
                if (DEBUG_TRANSITION) Slog.v(TAG,
                        "Prepare close transition: prev=" + prev);
                if (mNoAnimActivities.contains(prev)) {
                    anim = false;
                    mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
                } else {
                    mWindowManager.prepareAppTransition(prev.task == next.task
                            ? AppTransition.TRANSIT_ACTIVITY_CLOSE
                            : AppTransition.TRANSIT_TASK_CLOSE, false);
                }
                mWindowManager.setAppWillBeHidden(prev.appToken);
                mWindowManager.setAppVisibility(prev.appToken, false);
            } else {
                if (DEBUG_TRANSITION) Slog.v(TAG, "Prepare open transition: prev=" + prev);
                if (mNoAnimActivities.contains(next)) {
                    anim = false;
                    mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
                } else {
                    mWindowManager.prepareAppTransition(prev.task == next.task
                            ? AppTransition.TRANSIT_ACTIVITY_OPEN
                            : next.mLaunchTaskBehind
                                    ? AppTransition.TRANSIT_TASK_OPEN_BEHIND
                                    : AppTransition.TRANSIT_TASK_OPEN, false);
                }
            }
            if (false) {
                mWindowManager.setAppWillBeHidden(prev.appToken);
                mWindowManager.setAppVisibility(prev.appToken, false);
            }
        } else {
            if (DEBUG_TRANSITION) Slog.v(TAG, "Prepare open transition: no previous");
            if (mNoAnimActivities.contains(next)) {
                anim = false;
                mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, false);
            } else {
                mWindowManager.prepareAppTransition(AppTransition.TRANSIT_ACTIVITY_OPEN, false);
            }
        }

        Bundle resumeAnimOptions = null;
        if (anim) {
            ActivityOptions opts = next.getOptionsForTargetActivityLocked();
            if (opts != null) {
                resumeAnimOptions = opts.toBundle();
            }
            next.applyOptionsLocked();
        } else {
            next.clearOptionsLocked();
        }

        ActivityStack lastStack = mStackSupervisor.getLastStack();
        if (next.app != null && next.app.thread != null) {
            if (DEBUG_SWITCH) Slog.v(TAG, "Resume running: " + next);

            // This activity is now becoming visible.
            mWindowManager.setAppVisibility(next.appToken, true);

            // schedule launch ticks to collect information about slow apps.
            next.startLaunchTickingLocked();

            ActivityRecord lastResumedActivity =
                    lastStack == null ? null :lastStack.mResumedActivity;
            ActivityState lastState = next.state;

            mService.updateCpuStats();

            if (DEBUG_STATES) Slog.v(TAG, "Moving to RESUMED: " + next + " (in existing)");
            next.state = ActivityState.RESUMED;
            mResumedActivity = next;
            next.task.touchActiveTime();
            mService.addRecentTaskLocked(next.task);
            mService.updateLruProcessLocked(next.app, true, null);
            updateLRUListLocked(next);
            mService.updateOomAdjLocked();

            // Have the window manager re-evaluate the orientation of
            // the screen based on the new activity order.
            boolean notUpdated = true;
            if (mStackSupervisor.isFrontStack(this)) {
                Configuration config = mWindowManager.updateOrientationFromAppTokens(
                        mService.mConfiguration,
                        next.mayFreezeScreenLocked(next.app) ? next.appToken : null);
                if (config != null) {
                    next.frozenBeforeDestroy = true;
                }
                notUpdated = !mService.updateConfigurationLocked(config, next, false, false);
            }

            if (notUpdated) {
                // The configuration update wasn't able to keep the existing
                // instance of the activity, and instead started a new one.
                // We should be all done, but let's just make sure our activity
                // is still at the top and schedule another run if something
                // weird happened.
                ActivityRecord nextNext = topRunningActivityLocked(null);
                if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG,
                        "Activity config changed during resume: " + next
                        + ", new next: " + nextNext);
                if (nextNext != next) {
                    // Do over!
                    mStackSupervisor.scheduleResumeTopActivities();
                }
                if (mStackSupervisor.reportResumedActivityLocked(next)) {
                    mNoAnimActivities.clear();
                    if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
                    return true;
                }
                if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
                return false;
            }

            try {
                // Deliver all pending results.
                ArrayList<ResultInfo> a = next.results;
                if (a != null) {
                    final int N = a.size();
                    if (!next.finishing && N > 0) {
                        if (DEBUG_RESULTS) Slog.v(
                                TAG, "Delivering results to " + next
                                + ": " + a);
                        next.app.thread.scheduleSendResult(next.appToken, a);
                    }
                }

                if (next.newIntents != null) {
                    next.app.thread.scheduleNewIntent(next.newIntents, next.appToken);
                }

                EventLog.writeEvent(EventLogTags.AM_RESUME_ACTIVITY, next.userId,
                        System.identityHashCode(next), next.task.taskId, next.shortComponentName);

                next.sleeping = false;
                mService.showAskCompatModeDialogLocked(next);
                next.app.pendingUiClean = true;
                next.app.forceProcessStateUpTo(ActivityManager.PROCESS_STATE_TOP);
                next.clearOptionsLocked();
                next.app.thread.scheduleResumeActivity(next.appToken, next.app.repProcState,
                        mService.isNextTransitionForward(), resumeAnimOptions);

                mStackSupervisor.checkReadyForSleepLocked();

                if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: Resumed " + next);
            } catch (Exception e) {
                // Whoops, need to restart this activity!
                if (DEBUG_STATES) Slog.v(TAG, "Resume failed; resetting state to "
                        + lastState + ": " + next);
                next.state = lastState;
                if (lastStack != null) {
                    lastStack.mResumedActivity = lastResumedActivity;
                }
                Slog.i(TAG, "Restarting because process died: " + next);
                if (!next.hasBeenLaunched) {
                    next.hasBeenLaunched = true;
                } else  if (SHOW_APP_STARTING_PREVIEW && lastStack != null &&
                        mStackSupervisor.isFrontStack(lastStack)) {
                    mWindowManager.setAppStartingWindow(
                            next.appToken, next.packageName, next.theme,
                            mService.compatibilityInfoForPackageLocked(next.info.applicationInfo),
                            next.nonLocalizedLabel, next.labelRes, next.icon, next.logo,
                            next.windowFlags, null, true);
                }
                mStackSupervisor.startSpecificActivityLocked(next, true, false);
                if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
                return true;
            }

            // From this point on, if something goes wrong there is no way
            // to recover the activity.
            try {
                next.visible = true;
                completeResumeLocked(next);
            } catch (Exception e) {
                // If any exception gets thrown, toss away this
                // activity and try the next one.
                Slog.w(TAG, "Exception thrown during resume of " + next, e);
                requestFinishActivityLocked(next.appToken, Activity.RESULT_CANCELED, null,
                        "resume-exception", true);
                if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
                return true;
            }
            next.stopped = false;

        } else {
            // Whoops, need to restart this activity!
            if (!next.hasBeenLaunched) {
                next.hasBeenLaunched = true;
            } else {
                if (SHOW_APP_STARTING_PREVIEW) {
                    mWindowManager.setAppStartingWindow(
                            next.appToken, next.packageName, next.theme,
                            mService.compatibilityInfoForPackageLocked(
                                    next.info.applicationInfo),
                            next.nonLocalizedLabel,
                            next.labelRes, next.icon, next.logo, next.windowFlags,
                            null, true);
                }
                if (DEBUG_SWITCH) Slog.v(TAG, "Restarting: " + next);
            }
            if (DEBUG_STATES) Slog.d(TAG, "resumeTopActivityLocked: Restarting " + next);
            mStackSupervisor.startSpecificActivityLocked(next, true, true);
        }

        if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
        return true;
final booleanresumeTopActivityLocked(ActivityRecord prev)
Ensure that the top activity in the stack is resumed.

param
prev The previously resumed activity, for when in the process of pausing; can be null to call from elsewhere.
return
Returns true if something is being resumed, or false if nothing happened.

        return resumeTopActivityLocked(prev, null);
final booleanresumeTopActivityLocked(ActivityRecord prev, android.os.Bundle options)

        if (mStackSupervisor.inResumeTopActivity) {
            // Don't even start recursing.
            return false;
        }

        boolean result = false;
        try {
            // Protect against recursion.
            mStackSupervisor.inResumeTopActivity = true;
            if (mService.mLockScreenShown == ActivityManagerService.LOCK_SCREEN_LEAVING) {
                mService.mLockScreenShown = ActivityManagerService.LOCK_SCREEN_HIDDEN;
                mService.updateSleepIfNeededLocked();
            }
            result = resumeTopActivityInnerLocked(prev, options);
        } finally {
            mStackSupervisor.inResumeTopActivity = false;
        }
        return result;
final booleansafelyDestroyActivityLocked(ActivityRecord r, java.lang.String reason)

        if (r.isDestroyable()) {
            if (DEBUG_SWITCH) Slog.v(TAG, "Destroying " + r + " in state " + r.state
                    + " resumed=" + mResumedActivity
                    + " pausing=" + mPausingActivity + " for reason " + reason);
            return destroyActivityLocked(r, true, reason);
        }
        return false;
final voidscheduleDestroyActivities(ProcessRecord owner, java.lang.String reason)

        Message msg = mHandler.obtainMessage(DESTROY_ACTIVITIES_MSG);
        msg.obj = new ScheduleDestroyArgs(owner, reason);
        mHandler.sendMessage(msg);
public final android.graphics.BitmapscreenshotActivities(ActivityRecord who)

        if (DEBUG_SCREENSHOTS) Slog.d(TAG, "screenshotActivities: " + who);
        if (who.noDisplay) {
            if (DEBUG_SCREENSHOTS) Slog.d(TAG, "\tNo display");
            return null;
        }

        if (isHomeStack()) {
            // This is an optimization -- since we never show Home or Recents within Recents itself,
            // we can just go ahead and skip taking the screenshot if this is the home stack.
            if (DEBUG_SCREENSHOTS) Slog.d(TAG, "\tHome stack");
            return null;
        }

        int w = mService.mThumbnailWidth;
        int h = mService.mThumbnailHeight;
        if (w > 0) {
            if (DEBUG_SCREENSHOTS) Slog.d(TAG, "\tTaking screenshot");
            return mWindowManager.screenshotApplications(who.appToken, Display.DEFAULT_DISPLAY,
                    w, h, SCREENSHOT_FORCE_565);
        }
        Slog.e(TAG, "Invalid thumbnail dimensions: " + w + "x" + h);
        return null;
voidsendActivityResultLocked(int callingUid, ActivityRecord r, java.lang.String resultWho, int requestCode, int resultCode, android.content.Intent data)


        if (callingUid > 0) {
            mService.grantUriPermissionFromIntentLocked(callingUid, r.packageName,
                    data, r.getUriPermissionsLocked(), r.userId);
        }

        if (DEBUG_RESULTS) Slog.v(TAG, "Send activity result to " + r
                + " : who=" + resultWho + " req=" + requestCode
                + " res=" + resultCode + " data=" + data);
        if (mResumedActivity == r && r.app != null && r.app.thread != null) {
            try {
                ArrayList<ResultInfo> list = new ArrayList<ResultInfo>();
                list.add(new ResultInfo(resultWho, requestCode,
                        resultCode, data));
                r.app.thread.scheduleSendResult(r.appToken, list);
                return;
            } catch (Exception e) {
                Slog.w(TAG, "Exception thrown sending result to " + r, e);
            }
        }

        r.addResultLocked(null, resultWho, requestCode, resultCode, data);
voidsetLaunchTime(ActivityRecord r)

        if (r.displayStartTime == 0) {
            r.fullyDrawnStartTime = r.displayStartTime = SystemClock.uptimeMillis();
            if (mLaunchStartTime == 0) {
                startLaunchTraces();
                mLaunchStartTime = mFullyDrawnStartTime = r.displayStartTime;
            }
        } else if (mLaunchStartTime == 0) {
            startLaunchTraces();
            mLaunchStartTime = mFullyDrawnStartTime = SystemClock.uptimeMillis();
        }
private voidsetVisibile(ActivityRecord r, boolean visible)

        r.visible = visible;
        mWindowManager.setAppVisibility(r.appToken, visible);
        final ArrayList<ActivityContainer> containers = r.mChildContainers;
        for (int containerNdx = containers.size() - 1; containerNdx >= 0; --containerNdx) {
            ActivityContainer container = containers.get(containerNdx);
            container.setVisible(visible);
        }
voidsetVisibleBehindActivity(ActivityRecord r)

        if (isAttached()) {
            mActivityContainer.mActivityDisplay.setVisibleBehindActivity(r);
        }
final booleanshouldUpRecreateTaskLocked(ActivityRecord srec, java.lang.String destAffinity)

        // Basic case: for simple app-centric recents, we need to recreate
        // the task if the affinity has changed.
        if (srec == null || srec.task.affinity == null ||
                !srec.task.affinity.equals(destAffinity)) {
            return true;
        }
        // Document-centric case: an app may be split in to multiple documents;
        // they need to re-create their task if this current activity is the root
        // of a document, unless simply finishing it will return them to the the
        // correct app behind.
        if (srec.frontOfTask && srec.task != null && srec.task.getBaseIntent() != null
                && srec.task.getBaseIntent().isDocument()) {
            // Okay, this activity is at the root of its task.  What to do, what to do...
            if (srec.task.getTaskToReturnTo() != ActivityRecord.APPLICATION_ACTIVITY_TYPE) {
                // Finishing won't return to an application, so we need to recreate.
                return true;
            }
            // We now need to get the task below it to determine what to do.
            int taskIdx = mTaskHistory.indexOf(srec.task);
            if (taskIdx <= 0) {
                Slog.w(TAG, "shouldUpRecreateTask: task not in history for " + srec);
                return false;
            }
            if (taskIdx == 0) {
                // At the bottom of the stack, nothing to go back to.
                return true;
            }
            TaskRecord prevTask = mTaskHistory.get(taskIdx);
            if (!srec.task.affinity.equals(prevTask.affinity)) {
                // These are different apps, so need to recreate.
                return true;
            }
        }
        return false;
final voidstartActivityLocked(ActivityRecord r, boolean newTask, boolean doResume, boolean keepCurTransition, android.os.Bundle options)

        TaskRecord rTask = r.task;
        final int taskId = rTask.taskId;
        // mLaunchTaskBehind tasks get placed at the back of the task stack.
        if (!r.mLaunchTaskBehind && (taskForIdLocked(taskId) == null || newTask)) {
            // Last activity in task had been removed or ActivityManagerService is reusing task.
            // Insert or replace.
            // Might not even be in.
            insertTaskAtTop(rTask);
            mWindowManager.moveTaskToTop(taskId);
        }
        TaskRecord task = null;
        if (!newTask) {
            // If starting in an existing task, find where that is...
            boolean startIt = true;
            for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
                task = mTaskHistory.get(taskNdx);
                if (task.getTopActivity() == null) {
                    // All activities in task are finishing.
                    continue;
                }
                if (task == r.task) {
                    // Here it is!  Now, if this is not yet visible to the
                    // user, then just add it without starting; it will
                    // get started when the user navigates back to it.
                    if (!startIt) {
                        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to task "
                                + task, new RuntimeException("here").fillInStackTrace());
                        task.addActivityToTop(r);
                        r.putInHistory();
                        mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
                                r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
                                (r.info.flags & ActivityInfo.FLAG_SHOW_ON_LOCK_SCREEN) != 0,
                                r.userId, r.info.configChanges, task.voiceSession != null,
                                r.mLaunchTaskBehind);
                        if (VALIDATE_TOKENS) {
                            validateAppTokensLocked();
                        }
                        ActivityOptions.abort(options);
                        return;
                    }
                    break;
                } else if (task.numFullscreen > 0) {
                    startIt = false;
                }
            }
        }

        // Place a new activity at top of stack, so it is next to interact
        // with the user.

        // If we are not placing the new activity frontmost, we do not want
        // to deliver the onUserLeaving callback to the actual frontmost
        // activity
        if (task == r.task && mTaskHistory.indexOf(task) != (mTaskHistory.size() - 1)) {
            mStackSupervisor.mUserLeaving = false;
            if (DEBUG_USER_LEAVING) Slog.v(TAG,
                    "startActivity() behind front, mUserLeaving=false");
        }

        task = r.task;

        // Slot the activity into the history stack and proceed
        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to stack to task " + task,
                new RuntimeException("here").fillInStackTrace());
        task.addActivityToTop(r);
        task.setFrontOfTask();

        r.putInHistory();
        if (!isHomeStack() || numActivities() > 0) {
            // We want to show the starting preview window if we are
            // switching to a new task, or the next activity's process is
            // not currently running.
            boolean showStartingIcon = newTask;
            ProcessRecord proc = r.app;
            if (proc == null) {
                proc = mService.mProcessNames.get(r.processName, r.info.applicationInfo.uid);
            }
            if (proc == null || proc.thread == null) {
                showStartingIcon = true;
            }
            if (DEBUG_TRANSITION) Slog.v(TAG,
                    "Prepare open transition: starting " + r);
            if ((r.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
                mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, keepCurTransition);
                mNoAnimActivities.add(r);
            } else {
                mWindowManager.prepareAppTransition(newTask
                        ? r.mLaunchTaskBehind
                                ? AppTransition.TRANSIT_TASK_OPEN_BEHIND
                                : AppTransition.TRANSIT_TASK_OPEN
                        : AppTransition.TRANSIT_ACTIVITY_OPEN, keepCurTransition);
                mNoAnimActivities.remove(r);
            }
            mWindowManager.addAppToken(task.mActivities.indexOf(r),
                    r.appToken, r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
                    (r.info.flags & ActivityInfo.FLAG_SHOW_ON_LOCK_SCREEN) != 0, r.userId,
                    r.info.configChanges, task.voiceSession != null, r.mLaunchTaskBehind);
            boolean doShow = true;
            if (newTask) {
                // Even though this activity is starting fresh, we still need
                // to reset it to make sure we apply affinities to move any
                // existing activities from other tasks in to it.
                // If the caller has requested that the target task be
                // reset, then do so.
                if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) != 0) {
                    resetTaskIfNeededLocked(r, r);
                    doShow = topRunningNonDelayedActivityLocked(null) == r;
                }
            } else if (options != null && new ActivityOptions(options).getAnimationType()
                    == ActivityOptions.ANIM_SCENE_TRANSITION) {
                doShow = false;
            }
            if (r.mLaunchTaskBehind) {
                // Don't do a starting window for mLaunchTaskBehind. More importantly make sure we
                // tell WindowManager that r is visible even though it is at the back of the stack.
                mWindowManager.setAppVisibility(r.appToken, true);
                ensureActivitiesVisibleLocked(null, 0);
            } else if (SHOW_APP_STARTING_PREVIEW && doShow) {
                // Figure out if we are transitioning from another activity that is
                // "has the same starting icon" as the next one.  This allows the
                // window manager to keep the previous window it had previously
                // created, if it still had one.
                ActivityRecord prev = mResumedActivity;
                if (prev != null) {
                    // We don't want to reuse the previous starting preview if:
                    // (1) The current activity is in a different task.
                    if (prev.task != r.task) {
                        prev = null;
                    }
                    // (2) The current activity is already displayed.
                    else if (prev.nowVisible) {
                        prev = null;
                    }
                }
                mWindowManager.setAppStartingWindow(
                        r.appToken, r.packageName, r.theme,
                        mService.compatibilityInfoForPackageLocked(
                                r.info.applicationInfo), r.nonLocalizedLabel,
                        r.labelRes, r.icon, r.logo, r.windowFlags,
                        prev != null ? prev.appToken : null, showStartingIcon);
                r.mStartingWindowShown = true;
            }
        } else {
            // If this is the first activity, don't do any fancy animations,
            // because there is nothing for it to animate on top of.
            mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
                    r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
                    (r.info.flags & ActivityInfo.FLAG_SHOW_ON_LOCK_SCREEN) != 0, r.userId,
                    r.info.configChanges, task.voiceSession != null, r.mLaunchTaskBehind);
            ActivityOptions.abort(options);
            options = null;
        }
        if (VALIDATE_TOKENS) {
            validateAppTokensLocked();
        }

        if (doResume) {
            mStackSupervisor.resumeTopActivitiesLocked(this, r, options);
        }
private voidstartLaunchTraces()

        if (mFullyDrawnStartTime != 0)  {
            Trace.asyncTraceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER, "drawing", 0);
        }
        Trace.asyncTraceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "launching", 0);
        Trace.asyncTraceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "drawing", 0);
final booleanstartPausingLocked(boolean userLeaving, boolean uiSleeping, boolean resuming, boolean dontWait)
Start pausing the currently resumed activity. It is an error to call this if there is already an activity being paused or there is no resumed activity.

param
userLeaving True if this should result in an onUserLeaving to the current activity.
param
uiSleeping True if this is happening with the user interface going to sleep (the screen turning off).
param
resuming True if this is being called as part of resuming the top activity, so we shouldn't try to instigate a resume here.
param
dontWait True if the caller does not want to wait for the pause to complete. If set to true, we will immediately complete the pause here before returning.
return
Returns true if an activity now is in the PAUSING state, and we are waiting for it to tell us when it is done.

        if (mPausingActivity != null) {
            Slog.wtf(TAG, "Going to pause when pause is already pending for " + mPausingActivity);
            completePauseLocked(false);
        }
        ActivityRecord prev = mResumedActivity;
        if (prev == null) {
            if (!resuming) {
                Slog.wtf(TAG, "Trying to pause when nothing is resumed");
                mStackSupervisor.resumeTopActivitiesLocked();
            }
            return false;
        }

        if (mActivityContainer.mParentActivity == null) {
            // Top level stack, not a child. Look for child stacks.
            mStackSupervisor.pauseChildStacks(prev, userLeaving, uiSleeping, resuming, dontWait);
        }

        if (DEBUG_STATES) Slog.v(TAG, "Moving to PAUSING: " + prev);
        else if (DEBUG_PAUSE) Slog.v(TAG, "Start pausing: " + prev);
        mResumedActivity = null;
        mPausingActivity = prev;
        mLastPausedActivity = prev;
        mLastNoHistoryActivity = (prev.intent.getFlags() & Intent.FLAG_ACTIVITY_NO_HISTORY) != 0
                || (prev.info.flags & ActivityInfo.FLAG_NO_HISTORY) != 0 ? prev : null;
        prev.state = ActivityState.PAUSING;
        prev.task.touchActiveTime();
        clearLaunchTime(prev);
        final ActivityRecord next = mStackSupervisor.topRunningActivityLocked();
        if (mService.mHasRecents && (next == null || next.noDisplay || next.task != prev.task || uiSleeping)) {
            prev.updateThumbnailLocked(screenshotActivities(prev), null);
        }
        stopFullyDrawnTraceIfNeeded();

        mService.updateCpuStats();

        if (prev.app != null && prev.app.thread != null) {
            if (DEBUG_PAUSE) Slog.v(TAG, "Enqueueing pending pause: " + prev);
            try {
                EventLog.writeEvent(EventLogTags.AM_PAUSE_ACTIVITY,
                        prev.userId, System.identityHashCode(prev),
                        prev.shortComponentName);
                mService.updateUsageStats(prev, false);
                prev.app.thread.schedulePauseActivity(prev.appToken, prev.finishing,
                        userLeaving, prev.configChangeFlags, dontWait);
            } catch (Exception e) {
                // Ignore exception, if process died other code will cleanup.
                Slog.w(TAG, "Exception thrown during pause", e);
                mPausingActivity = null;
                mLastPausedActivity = null;
                mLastNoHistoryActivity = null;
            }
        } else {
            mPausingActivity = null;
            mLastPausedActivity = null;
            mLastNoHistoryActivity = null;
        }

        // If we are not going to sleep, we want to ensure the device is
        // awake until the next activity is started.
        if (!mService.isSleepingOrShuttingDown()) {
            mStackSupervisor.acquireLaunchWakelock();
        }

        if (mPausingActivity != null) {
            // Have the window manager pause its key dispatching until the new
            // activity has started.  If we're pausing the activity just because
            // the screen is being turned off and the UI is sleeping, don't interrupt
            // key dispatch; the same activity will pick it up again on wakeup.
            if (!uiSleeping) {
                prev.pauseKeyDispatchingLocked();
            } else {
                if (DEBUG_PAUSE) Slog.v(TAG, "Key dispatch not paused for screen off");
            }

            if (dontWait) {
                // If the caller said they don't want to wait for the pause, then complete
                // the pause now.
                completePauseLocked(false);
                return false;

            } else {
                // Schedule a pause timeout in case the app doesn't respond.
                // We don't give it much time because this directly impacts the
                // responsiveness seen by the user.
                Message msg = mHandler.obtainMessage(PAUSE_TIMEOUT_MSG);
                msg.obj = prev;
                prev.pauseTime = SystemClock.uptimeMillis();
                mHandler.sendMessageDelayed(msg, PAUSE_TIMEOUT);
                if (DEBUG_PAUSE) Slog.v(TAG, "Waiting for pause to complete...");
                return true;
            }

        } else {
            // This activity failed to schedule the
            // pause, so just treat it as being paused now.
            if (DEBUG_PAUSE) Slog.v(TAG, "Activity not running, resuming next.");
            if (!resuming) {
                mStackSupervisor.getFocusedStack().resumeTopActivityLocked(null);
            }
            return false;
        }
final voidstopActivityLocked(ActivityRecord r)

        if (DEBUG_SWITCH) Slog.d(TAG, "Stopping: " + r);
        if ((r.intent.getFlags()&Intent.FLAG_ACTIVITY_NO_HISTORY) != 0
                || (r.info.flags&ActivityInfo.FLAG_NO_HISTORY) != 0) {
            if (!r.finishing) {
                if (!mService.isSleeping()) {
                    if (DEBUG_STATES) {
                        Slog.d(TAG, "no-history finish of " + r);
                    }
                    requestFinishActivityLocked(r.appToken, Activity.RESULT_CANCELED, null,
                            "no-history", false);
                } else {
                    if (DEBUG_STATES) Slog.d(TAG, "Not finishing noHistory " + r
                            + " on stop because we're just sleeping");
                }
            }
        }

        if (r.app != null && r.app.thread != null) {
            adjustFocusedActivityLocked(r, "stopActivity");
            r.resumeKeyDispatchingLocked();
            try {
                r.stopped = false;
                if (DEBUG_STATES) Slog.v(TAG, "Moving to STOPPING: " + r
                        + " (stop requested)");
                r.state = ActivityState.STOPPING;
                if (DEBUG_VISBILITY) Slog.v(
                        TAG, "Stopping visible=" + r.visible + " for " + r);
                if (!r.visible) {
                    mWindowManager.setAppVisibility(r.appToken, false);
                }
                r.app.thread.scheduleStopActivity(r.appToken, r.visible, r.configChangeFlags);
                if (mService.isSleepingOrShuttingDown()) {
                    r.setSleeping(true);
                }
                Message msg = mHandler.obtainMessage(STOP_TIMEOUT_MSG, r);
                mHandler.sendMessageDelayed(msg, STOP_TIMEOUT);
            } catch (Exception e) {
                // Maybe just ignore exceptions here...  if the process
                // has crashed, our death notification will clean things
                // up.
                Slog.w(TAG, "Exception thrown during pause", e);
                // Just in case, assume it to be stopped.
                r.stopped = true;
                if (DEBUG_STATES) Slog.v(TAG, "Stop failed; moving to STOPPED: " + r);
                r.state = ActivityState.STOPPED;
                if (r.configDestroy) {
                    destroyActivityLocked(r, true, "stop-except");
                }
            }
        }
private voidstopFullyDrawnTraceIfNeeded()

        if (mFullyDrawnStartTime != 0 && mLaunchStartTime == 0) {
            Trace.asyncTraceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER, "drawing", 0);
            mFullyDrawnStartTime = 0;
        }
final voidswitchUserLocked(int userId)

        if (mCurrentUser == userId) {
            return;
        }
        mCurrentUser = userId;

        // Move userId's tasks to the top.
        int index = mTaskHistory.size();
        for (int i = 0; i < index; ) {
            TaskRecord task = mTaskHistory.get(i);
            if (isCurrentProfileLocked(task.userId)) {
                if (DEBUG_TASKS) Slog.d(TAG, "switchUserLocked: stack=" + getStackId() +
                        " moving " + task + " to top");
                mTaskHistory.remove(i);
                mTaskHistory.add(task);
                --index;
                // Use same value for i.
            } else {
                ++i;
            }
        }
        if (VALIDATE_TOKENS) {
            validateAppTokensLocked();
        }
TaskRecordtaskForIdLocked(int id)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            if (task.taskId == id) {
                return task;
            }
        }
        return null;
public java.lang.StringtoString()

        return "ActivityStack{" + Integer.toHexString(System.identityHashCode(this))
                + " stackId=" + mStackId + ", " + mTaskHistory.size() + " tasks}";
final ActivityRecordtopActivity()

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (!r.finishing) {
                    return r;
                }
            }
        }
        return null;
final ActivityRecordtopRunningActivityLocked(ActivityRecord notTop)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            ActivityRecord r = mTaskHistory.get(taskNdx).topRunningActivityLocked(notTop);
            if (r != null) {
                return r;
            }
        }
        return null;
final ActivityRecordtopRunningActivityLocked(android.os.IBinder token, int taskId)
This is a simplified version of topRunningActivityLocked that provides a number of optional skip-over modes. It is intended for use with the ActivityController hook only.

param
token If non-null, any history records matching this token will be skipped.
param
taskId If non-zero, we'll attempt to skip over records with the same task ID.
return
Returns the HistoryRecord of the next activity on the stack.

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            TaskRecord task = mTaskHistory.get(taskNdx);
            if (task.taskId == taskId) {
                continue;
            }
            ArrayList<ActivityRecord> activities = task.mActivities;
            for (int i = activities.size() - 1; i >= 0; --i) {
                final ActivityRecord r = activities.get(i);
                // Note: the taskId check depends on real taskId fields being non-zero
                if (!r.finishing && (token != r.appToken) && okToShowLocked(r)) {
                    return r;
                }
            }
        }
        return null;
final ActivityRecordtopRunningNonDelayedActivityLocked(ActivityRecord notTop)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final TaskRecord task = mTaskHistory.get(taskNdx);
            final ArrayList<ActivityRecord> activities = task.mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                ActivityRecord r = activities.get(activityNdx);
                if (!r.finishing && !r.delayedResume && r != notTop && okToShowLocked(r)) {
                    return r;
                }
            }
        }
        return null;
final TaskRecordtopTask()

        final int size = mTaskHistory.size();
        if (size > 0) {
            return mTaskHistory.get(size - 1);
        }
        return null;
public voidunhandledBackLocked()

        final int top = mTaskHistory.size() - 1;
        if (DEBUG_SWITCH) Slog.d(
            TAG, "Performing unhandledBack(): top activity at " + top);
        if (top >= 0) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(top).mActivities;
            int activityTop = activities.size() - 1;
            if (activityTop > 0) {
                finishActivityLocked(activities.get(activityTop), Activity.RESULT_CANCELED, null,
                        "unhandled-back", true);
            }
        }
final booleanupdateLRUListLocked(ActivityRecord r)

        final boolean hadit = mLRUActivities.remove(r);
        mLRUActivities.add(r);
        return hadit;
voidupdateTaskMovement(TaskRecord task, boolean toFront)

        if (task.isPersistable) {
            task.mLastTimeMoved = System.currentTimeMillis();
            // Sign is used to keep tasks sorted when persisted. Tasks sent to the bottom most
            // recently will be most negative, tasks sent to the bottom before that will be less
            // negative. Similarly for recent tasks moved to the top which will be most positive.
            if (!toFront) {
                task.mLastTimeMoved *= -1;
            }
        }
final voidupdateTransitLocked(int transit, android.os.Bundle options)

        if (options != null) {
            ActivityRecord r = topRunningActivityLocked(null);
            if (r != null && r.state != ActivityState.RESUMED) {
                r.updateOptionsLocked(options);
            } else {
                ActivityOptions.abort(options);
            }
        }
        mWindowManager.prepareAppTransition(transit, false);
final voidvalidateAppTokensLocked()

        mValidateAppTokens.clear();
        mValidateAppTokens.ensureCapacity(numActivities());
        final int numTasks = mTaskHistory.size();
        for (int taskNdx = 0; taskNdx < numTasks; ++taskNdx) {
            TaskRecord task = mTaskHistory.get(taskNdx);
            final ArrayList<ActivityRecord> activities = task.mActivities;
            if (activities.isEmpty()) {
                continue;
            }
            TaskGroup group = new TaskGroup();
            group.taskId = task.taskId;
            mValidateAppTokens.add(group);
            final int numActivities = activities.size();
            for (int activityNdx = 0; activityNdx < numActivities; ++activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                group.tokens.add(r.appToken);
            }
        }
        mWindowManager.validateAppTokens(mStackId, mValidateAppTokens);
booleanwillActivityBeVisibleLocked(android.os.IBinder token)

        for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
            final ArrayList<ActivityRecord> activities = mTaskHistory.get(taskNdx).mActivities;
            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
                final ActivityRecord r = activities.get(activityNdx);
                if (r.appToken == token) {
                    return true;
                }
                if (r.fullscreen && !r.finishing) {
                    return false;
                }
            }
        }
        final ActivityRecord r = ActivityRecord.forToken(token);
        if (r == null) {
            return false;
        }
        if (r.finishing) Slog.e(TAG, "willActivityBeVisibleLocked: Returning false,"
                + " would have returned true for r=" + r);
        return !r.finishing;