/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.app;
import android.annotation.NonNull;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Bundle;
import android.os.UserHandle;
import android.util.Log;
import java.util.ArrayList;
/**
* Utility class for constructing synthetic back stacks for cross-task navigation
* on Android 3.0 and newer.
*
* <p>In API level 11 (Android 3.0/Honeycomb) the recommended conventions for
* app navigation using the back key changed. The back key's behavior is local
* to the current task and does not capture navigation across different tasks.
* Navigating across tasks and easily reaching the previous task is accomplished
* through the "recents" UI, accessible through the software-provided Recents key
* on the navigation or system bar. On devices with the older hardware button configuration
* the recents UI can be accessed with a long press on the Home key.</p>
*
* <p>When crossing from one task stack to another post-Android 3.0,
* the application should synthesize a back stack/history for the new task so that
* the user may navigate out of the new task and back to the Launcher by repeated
* presses of the back key. Back key presses should not navigate across task stacks.</p>
*
* <p>TaskStackBuilder provides a way to obey the correct conventions
* around cross-task navigation.</p>
*
* <div class="special reference">
* <h3>About Navigation</h3>
* For more detailed information about tasks, the back stack, and navigation design guidelines,
* please read
* <a href="{@docRoot}guide/topics/fundamentals/tasks-and-back-stack.html">Tasks and Back Stack</a>
* from the developer guide and <a href="{@docRoot}design/patterns/navigation.html">Navigation</a>
* from the design guide.
* </div>
*/
public class TaskStackBuilder {
private static final String TAG = "TaskStackBuilder";
private final ArrayList<Intent> mIntents = new ArrayList<Intent>();
private final Context mSourceContext;
private TaskStackBuilder(Context a) {
mSourceContext = a;
}
/**
* Return a new TaskStackBuilder for launching a fresh task stack consisting
* of a series of activities.
*
* @param context The context that will launch the new task stack or generate a PendingIntent
* @return A new TaskStackBuilder
*/
public static TaskStackBuilder create(Context context) {
return new TaskStackBuilder(context);
}
/**
* Add a new Intent to the task stack. The most recently added Intent will invoke
* the Activity at the top of the final task stack.
*
* @param nextIntent Intent for the next Activity in the synthesized task stack
* @return This TaskStackBuilder for method chaining
*/
public TaskStackBuilder addNextIntent(Intent nextIntent) {
mIntents.add(nextIntent);
return this;
}
/**
* Add a new Intent with the resolved chain of parents for the target activity to
* the task stack.
*
* <p>This is equivalent to calling {@link #addParentStack(ComponentName) addParentStack}
* with the resolved ComponentName of nextIntent (if it can be resolved), followed by
* {@link #addNextIntent(Intent) addNextIntent} with nextIntent.</p>
*
* @param nextIntent Intent for the topmost Activity in the synthesized task stack.
* Its chain of parents as specified in the manifest will be added.
* @return This TaskStackBuilder for method chaining.
*/
public TaskStackBuilder addNextIntentWithParentStack(Intent nextIntent) {
ComponentName target = nextIntent.getComponent();
if (target == null) {
target = nextIntent.resolveActivity(mSourceContext.getPackageManager());
}
if (target != null) {
addParentStack(target);
}
addNextIntent(nextIntent);
return this;
}
/**
* Add the activity parent chain as specified by the
* {@link Activity#getParentActivityIntent() getParentActivityIntent()} method of the activity
* specified and the {@link android.R.attr#parentActivityName parentActivityName} attributes
* of each successive activity (or activity-alias) element in the application's manifest
* to the task stack builder.
*
* @param sourceActivity All parents of this activity will be added
* @return This TaskStackBuilder for method chaining
*/
public TaskStackBuilder addParentStack(Activity sourceActivity) {
final Intent parent = sourceActivity.getParentActivityIntent();
if (parent != null) {
// We have the actual parent intent, build the rest from static metadata
// then add the direct parent intent to the end.
ComponentName target = parent.getComponent();
if (target == null) {
target = parent.resolveActivity(mSourceContext.getPackageManager());
}
addParentStack(target);
addNextIntent(parent);
}
return this;
}
/**
* Add the activity parent chain as specified by the
* {@link android.R.attr#parentActivityName parentActivityName} attribute of the activity
* (or activity-alias) element in the application's manifest to the task stack builder.
*
* @param sourceActivityClass All parents of this activity will be added
* @return This TaskStackBuilder for method chaining
*/
public TaskStackBuilder addParentStack(Class<?> sourceActivityClass) {
return addParentStack(new ComponentName(mSourceContext, sourceActivityClass));
}
/**
* Add the activity parent chain as specified by the
* {@link android.R.attr#parentActivityName parentActivityName} attribute of the activity
* (or activity-alias) element in the application's manifest to the task stack builder.
*
* @param sourceActivityName Must specify an Activity component. All parents of
* this activity will be added
* @return This TaskStackBuilder for method chaining
*/
public TaskStackBuilder addParentStack(ComponentName sourceActivityName) {
final int insertAt = mIntents.size();
PackageManager pm = mSourceContext.getPackageManager();
try {
ActivityInfo info = pm.getActivityInfo(sourceActivityName, 0);
String parentActivity = info.parentActivityName;
while (parentActivity != null) {
final ComponentName target = new ComponentName(info.packageName, parentActivity);
info = pm.getActivityInfo(target, 0);
parentActivity = info.parentActivityName;
final Intent parent = parentActivity == null && insertAt == 0
? Intent.makeMainActivity(target)
: new Intent().setComponent(target);
mIntents.add(insertAt, parent);
}
} catch (NameNotFoundException e) {
Log.e(TAG, "Bad ComponentName while traversing activity parent metadata");
throw new IllegalArgumentException(e);
}
return this;
}
/**
* @return the number of intents added so far.
*/
public int getIntentCount() {
return mIntents.size();
}
/**
* Return the intent at the specified index for modification.
* Useful if you need to modify the flags or extras of an intent that was previously added,
* for example with {@link #addParentStack(Activity)}.
*
* @param index Index from 0-getIntentCount()
* @return the intent at position index
*/
public Intent editIntentAt(int index) {
return mIntents.get(index);
}
/**
* Start the task stack constructed by this builder.
*/
public void startActivities() {
startActivities(null);
}
/**
* Start the task stack constructed by this builder.
* @hide
*/
public void startActivities(Bundle options, UserHandle userHandle) {
if (mIntents.isEmpty()) {
throw new IllegalStateException(
"No intents added to TaskStackBuilder; cannot startActivities");
}
mSourceContext.startActivitiesAsUser(getIntents(), options, userHandle);
}
/**
* Start the task stack constructed by this builder.
*
* @param options Additional options for how the Activity should be started.
* See {@link android.content.Context#startActivity(Intent, Bundle)
* Context.startActivity(Intent, Bundle)} for more details.
*/
public void startActivities(Bundle options) {
startActivities(options, new UserHandle(UserHandle.myUserId()));
}
/**
* Obtain a {@link PendingIntent} for launching the task constructed by this builder so far.
*
* @param requestCode Private request code for the sender
* @param flags May be {@link PendingIntent#FLAG_ONE_SHOT},
* {@link PendingIntent#FLAG_NO_CREATE}, {@link PendingIntent#FLAG_CANCEL_CURRENT},
* {@link PendingIntent#FLAG_UPDATE_CURRENT}, or any of the flags supported by
* {@link Intent#fillIn(Intent, int)} to control which unspecified parts of the
* intent that can be supplied when the actual send happens.
*
* @return The obtained PendingIntent
*/
public PendingIntent getPendingIntent(int requestCode, @PendingIntent.Flags int flags) {
return getPendingIntent(requestCode, flags, null);
}
/**
* Obtain a {@link PendingIntent} for launching the task constructed by this builder so far.
*
* @param requestCode Private request code for the sender
* @param flags May be {@link PendingIntent#FLAG_ONE_SHOT},
* {@link PendingIntent#FLAG_NO_CREATE}, {@link PendingIntent#FLAG_CANCEL_CURRENT},
* {@link PendingIntent#FLAG_UPDATE_CURRENT}, or any of the flags supported by
* {@link Intent#fillIn(Intent, int)} to control which unspecified parts of the
* intent that can be supplied when the actual send happens.
* @param options Additional options for how the Activity should be started.
* See {@link android.content.Context#startActivity(Intent, Bundle)
* Context.startActivity(Intent, Bundle)} for more details.
*
* @return The obtained PendingIntent
*/
public PendingIntent getPendingIntent(int requestCode, @PendingIntent.Flags int flags,
Bundle options) {
if (mIntents.isEmpty()) {
throw new IllegalStateException(
"No intents added to TaskStackBuilder; cannot getPendingIntent");
}
return PendingIntent.getActivities(mSourceContext, requestCode, getIntents(),
flags, options);
}
/**
* @hide
*/
public PendingIntent getPendingIntent(int requestCode, int flags, Bundle options,
UserHandle user) {
if (mIntents.isEmpty()) {
throw new IllegalStateException(
"No intents added to TaskStackBuilder; cannot getPendingIntent");
}
return PendingIntent.getActivitiesAsUser(mSourceContext, requestCode, getIntents(), flags,
options, user);
}
/**
* Return an array containing the intents added to this builder. The intent at the
* root of the task stack will appear as the first item in the array and the
* intent at the top of the stack will appear as the last item.
*
* @return An array containing the intents added to this builder.
*/
@NonNull
public Intent[] getIntents() {
Intent[] intents = new Intent[mIntents.size()];
if (intents.length == 0) return intents;
intents[0] = new Intent(mIntents.get(0)).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
Intent.FLAG_ACTIVITY_CLEAR_TASK |
Intent.FLAG_ACTIVITY_TASK_ON_HOME);
for (int i = 1; i < intents.length; i++) {
intents[i] = new Intent(mIntents.get(i));
}
return intents;
}
}
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