/*
* Copyright (C) 2009 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.view.accessibility;
import android.Manifest;
import android.accessibilityservice.AccessibilityServiceInfo;
import android.annotation.NonNull;
import android.content.Context;
import android.content.pm.PackageManager;
import android.content.pm.ServiceInfo;
import android.os.Binder;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.Process;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.os.UserHandle;
import android.util.Log;
import android.view.IWindow;
import android.view.View;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* System level service that serves as an event dispatch for {@link AccessibilityEvent}s,
* and provides facilities for querying the accessibility state of the system.
* Accessibility events are generated when something notable happens in the user interface,
* for example an {@link android.app.Activity} starts, the focus or selection of a
* {@link android.view.View} changes etc. Parties interested in handling accessibility
* events implement and register an accessibility service which extends
* {@link android.accessibilityservice.AccessibilityService}.
* <p>
* To obtain a handle to the accessibility manager do the following:
* </p>
* <p>
* <code>
* <pre>AccessibilityManager accessibilityManager =
* (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE);</pre>
* </code>
* </p>
*
* @see AccessibilityEvent
* @see AccessibilityNodeInfo
* @see android.accessibilityservice.AccessibilityService
* @see Context#getSystemService
* @see Context#ACCESSIBILITY_SERVICE
*/
public final class AccessibilityManager {
private static final boolean DEBUG = false;
private static final String LOG_TAG = "AccessibilityManager";
/** @hide */
public static final int STATE_FLAG_ACCESSIBILITY_ENABLED = 0x00000001;
/** @hide */
public static final int STATE_FLAG_TOUCH_EXPLORATION_ENABLED = 0x00000002;
/** @hide */
public static final int STATE_FLAG_HIGH_TEXT_CONTRAST_ENABLED = 0x00000004;
/** @hide */
public static final int DALTONIZER_DISABLED = -1;
/** @hide */
public static final int DALTONIZER_SIMULATE_MONOCHROMACY = 0;
/** @hide */
public static final int DALTONIZER_CORRECT_DEUTERANOMALY = 12;
static final Object sInstanceSync = new Object();
private static AccessibilityManager sInstance;
private final Object mLock = new Object();
private IAccessibilityManager mService;
final int mUserId;
final Handler mHandler;
boolean mIsEnabled;
boolean mIsTouchExplorationEnabled;
boolean mIsHighTextContrastEnabled;
private final CopyOnWriteArrayList<AccessibilityStateChangeListener>
mAccessibilityStateChangeListeners = new CopyOnWriteArrayList<>();
private final CopyOnWriteArrayList<TouchExplorationStateChangeListener>
mTouchExplorationStateChangeListeners = new CopyOnWriteArrayList<>();
private final CopyOnWriteArrayList<HighTextContrastChangeListener>
mHighTextContrastStateChangeListeners = new CopyOnWriteArrayList<>();
/**
* Listener for the system accessibility state. To listen for changes to the
* accessibility state on the device, implement this interface and register
* it with the system by calling {@link #addAccessibilityStateChangeListener}.
*/
public interface AccessibilityStateChangeListener {
/**
* Called when the accessibility enabled state changes.
*
* @param enabled Whether accessibility is enabled.
*/
public void onAccessibilityStateChanged(boolean enabled);
}
/**
* Listener for the system touch exploration state. To listen for changes to
* the touch exploration state on the device, implement this interface and
* register it with the system by calling
* {@link #addTouchExplorationStateChangeListener}.
*/
public interface TouchExplorationStateChangeListener {
/**
* Called when the touch exploration enabled state changes.
*
* @param enabled Whether touch exploration is enabled.
*/
public void onTouchExplorationStateChanged(boolean enabled);
}
/**
* Listener for the system high text contrast state. To listen for changes to
* the high text contrast state on the device, implement this interface and
* register it with the system by calling
* {@link #addHighTextContrastStateChangeListener}.
*
* @hide
*/
public interface HighTextContrastChangeListener {
/**
* Called when the high text contrast enabled state changes.
*
* @param enabled Whether high text contrast is enabled.
*/
public void onHighTextContrastStateChanged(boolean enabled);
}
private final IAccessibilityManagerClient.Stub mClient =
new IAccessibilityManagerClient.Stub() {
public void setState(int state) {
// We do not want to change this immediately as the applicatoin may
// have already checked that accessibility is on and fired an event,
// that is now propagating up the view tree, Hence, if accessibility
// is now off an exception will be thrown. We want to have the exception
// enforcement to guard against apps that fire unnecessary accessibility
// events when accessibility is off.
mHandler.obtainMessage(MyHandler.MSG_SET_STATE, state, 0).sendToTarget();
}
};
/**
* Get an AccessibilityManager instance (create one if necessary).
*
* @param context Context in which this manager operates.
*
* @hide
*/
public static AccessibilityManager getInstance(Context context) {
synchronized (sInstanceSync) {
if (sInstance == null) {
final int userId;
if (Binder.getCallingUid() == Process.SYSTEM_UID
|| context.checkCallingOrSelfPermission(
Manifest.permission.INTERACT_ACROSS_USERS)
== PackageManager.PERMISSION_GRANTED
|| context.checkCallingOrSelfPermission(
Manifest.permission.INTERACT_ACROSS_USERS_FULL)
== PackageManager.PERMISSION_GRANTED) {
userId = UserHandle.USER_CURRENT;
} else {
userId = UserHandle.myUserId();
}
IBinder iBinder = ServiceManager.getService(Context.ACCESSIBILITY_SERVICE);
IAccessibilityManager service = iBinder == null
? null : IAccessibilityManager.Stub.asInterface(iBinder);
sInstance = new AccessibilityManager(context, service, userId);
}
}
return sInstance;
}
/**
* Create an instance.
*
* @param context A {@link Context}.
* @param service An interface to the backing service.
* @param userId User id under which to run.
*
* @hide
*/
public AccessibilityManager(Context context, IAccessibilityManager service, int userId) {
mHandler = new MyHandler(context.getMainLooper());
mService = service;
mUserId = userId;
synchronized (mLock) {
tryConnectToServiceLocked();
}
}
/**
* @hide
*/
public IAccessibilityManagerClient getClient() {
return mClient;
}
/**
* Returns if the accessibility in the system is enabled.
*
* @return True if accessibility is enabled, false otherwise.
*/
public boolean isEnabled() {
synchronized (mLock) {
IAccessibilityManager service = getServiceLocked();
if (service == null) {
return false;
}
return mIsEnabled;
}
}
/**
* Returns if the touch exploration in the system is enabled.
*
* @return True if touch exploration is enabled, false otherwise.
*/
public boolean isTouchExplorationEnabled() {
synchronized (mLock) {
IAccessibilityManager service = getServiceLocked();
if (service == null) {
return false;
}
return mIsTouchExplorationEnabled;
}
}
/**
* Returns if the high text contrast in the system is enabled.
* <p>
* <strong>Note:</strong> You need to query this only if you application is
* doing its own rendering and does not rely on the platform rendering pipeline.
* </p>
*
* @return True if high text contrast is enabled, false otherwise.
*
* @hide
*/
public boolean isHighTextContrastEnabled() {
synchronized (mLock) {
IAccessibilityManager service = getServiceLocked();
if (service == null) {
return false;
}
return mIsHighTextContrastEnabled;
}
}
/**
* Sends an {@link AccessibilityEvent}.
*
* @param event The event to send.
*
* @throws IllegalStateException if accessibility is not enabled.
*
* <strong>Note:</strong> The preferred mechanism for sending custom accessibility
* events is through calling
* {@link android.view.ViewParent#requestSendAccessibilityEvent(View, AccessibilityEvent)}
* instead of this method to allow predecessors to augment/filter events sent by
* their descendants.
*/
public void sendAccessibilityEvent(AccessibilityEvent event) {
final IAccessibilityManager service;
final int userId;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return;
}
if (!mIsEnabled) {
throw new IllegalStateException("Accessibility off. Did you forget to check that?");
}
userId = mUserId;
}
boolean doRecycle = false;
try {
event.setEventTime(SystemClock.uptimeMillis());
// it is possible that this manager is in the same process as the service but
// client using it is called through Binder from another process. Example: MMS
// app adds a SMS notification and the NotificationManagerService calls this method
long identityToken = Binder.clearCallingIdentity();
doRecycle = service.sendAccessibilityEvent(event, userId);
Binder.restoreCallingIdentity(identityToken);
if (DEBUG) {
Log.i(LOG_TAG, event + " sent");
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error during sending " + event + " ", re);
} finally {
if (doRecycle) {
event.recycle();
}
}
}
/**
* Requests feedback interruption from all accessibility services.
*/
public void interrupt() {
final IAccessibilityManager service;
final int userId;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return;
}
if (!mIsEnabled) {
throw new IllegalStateException("Accessibility off. Did you forget to check that?");
}
userId = mUserId;
}
try {
service.interrupt(userId);
if (DEBUG) {
Log.i(LOG_TAG, "Requested interrupt from all services");
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while requesting interrupt from all services. ", re);
}
}
/**
* Returns the {@link ServiceInfo}s of the installed accessibility services.
*
* @return An unmodifiable list with {@link ServiceInfo}s.
*
* @deprecated Use {@link #getInstalledAccessibilityServiceList()}
*/
@Deprecated
public List<ServiceInfo> getAccessibilityServiceList() {
List<AccessibilityServiceInfo> infos = getInstalledAccessibilityServiceList();
List<ServiceInfo> services = new ArrayList<>();
final int infoCount = infos.size();
for (int i = 0; i < infoCount; i++) {
AccessibilityServiceInfo info = infos.get(i);
services.add(info.getResolveInfo().serviceInfo);
}
return Collections.unmodifiableList(services);
}
/**
* Returns the {@link AccessibilityServiceInfo}s of the installed accessibility services.
*
* @return An unmodifiable list with {@link AccessibilityServiceInfo}s.
*/
public List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList() {
final IAccessibilityManager service;
final int userId;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return Collections.emptyList();
}
userId = mUserId;
}
List<AccessibilityServiceInfo> services = null;
try {
services = service.getInstalledAccessibilityServiceList(userId);
if (DEBUG) {
Log.i(LOG_TAG, "Installed AccessibilityServices " + services);
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while obtaining the installed AccessibilityServices. ", re);
}
if (services != null) {
return Collections.unmodifiableList(services);
} else {
return Collections.emptyList();
}
}
/**
* Returns the {@link AccessibilityServiceInfo}s of the enabled accessibility services
* for a given feedback type.
*
* @param feedbackTypeFlags The feedback type flags.
* @return An unmodifiable list with {@link AccessibilityServiceInfo}s.
*
* @see AccessibilityServiceInfo#FEEDBACK_AUDIBLE
* @see AccessibilityServiceInfo#FEEDBACK_GENERIC
* @see AccessibilityServiceInfo#FEEDBACK_HAPTIC
* @see AccessibilityServiceInfo#FEEDBACK_SPOKEN
* @see AccessibilityServiceInfo#FEEDBACK_VISUAL
* @see AccessibilityServiceInfo#FEEDBACK_BRAILLE
*/
public List<AccessibilityServiceInfo> getEnabledAccessibilityServiceList(
int feedbackTypeFlags) {
final IAccessibilityManager service;
final int userId;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return Collections.emptyList();
}
userId = mUserId;
}
List<AccessibilityServiceInfo> services = null;
try {
services = service.getEnabledAccessibilityServiceList(feedbackTypeFlags, userId);
if (DEBUG) {
Log.i(LOG_TAG, "Installed AccessibilityServices " + services);
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while obtaining the installed AccessibilityServices. ", re);
}
if (services != null) {
return Collections.unmodifiableList(services);
} else {
return Collections.emptyList();
}
}
/**
* Registers an {@link AccessibilityStateChangeListener} for changes in
* the global accessibility state of the system.
*
* @param listener The listener.
* @return True if successfully registered.
*/
public boolean addAccessibilityStateChangeListener(
@NonNull AccessibilityStateChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mAccessibilityStateChangeListeners.add(listener);
}
/**
* Unregisters an {@link AccessibilityStateChangeListener}.
*
* @param listener The listener.
* @return True if successfully unregistered.
*/
public boolean removeAccessibilityStateChangeListener(
@NonNull AccessibilityStateChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mAccessibilityStateChangeListeners.remove(listener);
}
/**
* Registers a {@link TouchExplorationStateChangeListener} for changes in
* the global touch exploration state of the system.
*
* @param listener The listener.
* @return True if successfully registered.
*/
public boolean addTouchExplorationStateChangeListener(
@NonNull TouchExplorationStateChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mTouchExplorationStateChangeListeners.add(listener);
}
/**
* Unregisters a {@link TouchExplorationStateChangeListener}.
*
* @param listener The listener.
* @return True if successfully unregistered.
*/
public boolean removeTouchExplorationStateChangeListener(
@NonNull TouchExplorationStateChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mTouchExplorationStateChangeListeners.remove(listener);
}
/**
* Registers a {@link HighTextContrastChangeListener} for changes in
* the global high text contrast state of the system.
*
* @param listener The listener.
* @return True if successfully registered.
*
* @hide
*/
public boolean addHighTextContrastStateChangeListener(
@NonNull HighTextContrastChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mHighTextContrastStateChangeListeners.add(listener);
}
/**
* Unregisters a {@link HighTextContrastChangeListener}.
*
* @param listener The listener.
* @return True if successfully unregistered.
*
* @hide
*/
public boolean removeHighTextContrastStateChangeListener(
@NonNull HighTextContrastChangeListener listener) {
// Final CopyOnWriteArrayList - no lock needed.
return mHighTextContrastStateChangeListeners.remove(listener);
}
/**
* Sets the current state and notifies listeners, if necessary.
*
* @param stateFlags The state flags.
*/
private void setStateLocked(int stateFlags) {
final boolean enabled = (stateFlags & STATE_FLAG_ACCESSIBILITY_ENABLED) != 0;
final boolean touchExplorationEnabled =
(stateFlags & STATE_FLAG_TOUCH_EXPLORATION_ENABLED) != 0;
final boolean highTextContrastEnabled =
(stateFlags & STATE_FLAG_HIGH_TEXT_CONTRAST_ENABLED) != 0;
final boolean wasEnabled = mIsEnabled;
final boolean wasTouchExplorationEnabled = mIsTouchExplorationEnabled;
final boolean wasHighTextContrastEnabled = mIsHighTextContrastEnabled;
// Ensure listeners get current state from isZzzEnabled() calls.
mIsEnabled = enabled;
mIsTouchExplorationEnabled = touchExplorationEnabled;
mIsHighTextContrastEnabled = highTextContrastEnabled;
if (wasEnabled != enabled) {
mHandler.sendEmptyMessage(MyHandler.MSG_NOTIFY_ACCESSIBILITY_STATE_CHANGED);
}
if (wasTouchExplorationEnabled != touchExplorationEnabled) {
mHandler.sendEmptyMessage(MyHandler.MSG_NOTIFY_EXPLORATION_STATE_CHANGED);
}
if (wasHighTextContrastEnabled != highTextContrastEnabled) {
mHandler.sendEmptyMessage(MyHandler.MSG_NOTIFY_HIGH_TEXT_CONTRAST_STATE_CHANGED);
}
}
/**
* Adds an accessibility interaction connection interface for a given window.
* @param windowToken The window token to which a connection is added.
* @param connection The connection.
*
* @hide
*/
public int addAccessibilityInteractionConnection(IWindow windowToken,
IAccessibilityInteractionConnection connection) {
final IAccessibilityManager service;
final int userId;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return View.NO_ID;
}
userId = mUserId;
}
try {
return service.addAccessibilityInteractionConnection(windowToken, connection, userId);
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while adding an accessibility interaction connection. ", re);
}
return View.NO_ID;
}
/**
* Removed an accessibility interaction connection interface for a given window.
* @param windowToken The window token to which a connection is removed.
*
* @hide
*/
public void removeAccessibilityInteractionConnection(IWindow windowToken) {
final IAccessibilityManager service;
synchronized (mLock) {
service = getServiceLocked();
if (service == null) {
return;
}
}
try {
service.removeAccessibilityInteractionConnection(windowToken);
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while removing an accessibility interaction connection. ", re);
}
}
private IAccessibilityManager getServiceLocked() {
if (mService == null) {
tryConnectToServiceLocked();
}
return mService;
}
private void tryConnectToServiceLocked() {
IBinder iBinder = ServiceManager.getService(Context.ACCESSIBILITY_SERVICE);
if (iBinder == null) {
return;
}
IAccessibilityManager service = IAccessibilityManager.Stub.asInterface(iBinder);
try {
final int stateFlags = service.addClient(mClient, mUserId);
setStateLocked(stateFlags);
mService = service;
} catch (RemoteException re) {
Log.e(LOG_TAG, "AccessibilityManagerService is dead", re);
}
}
/**
* Notifies the registered {@link AccessibilityStateChangeListener}s.
*/
private void handleNotifyAccessibilityStateChanged() {
final boolean isEnabled;
synchronized (mLock) {
isEnabled = mIsEnabled;
}
// Listeners are a final CopyOnWriteArrayList, hence no lock needed.
for (AccessibilityStateChangeListener listener :mAccessibilityStateChangeListeners) {
listener.onAccessibilityStateChanged(isEnabled);
}
}
/**
* Notifies the registered {@link TouchExplorationStateChangeListener}s.
*/
private void handleNotifyTouchExplorationStateChanged() {
final boolean isTouchExplorationEnabled;
synchronized (mLock) {
isTouchExplorationEnabled = mIsTouchExplorationEnabled;
}
// Listeners are a final CopyOnWriteArrayList, hence no lock needed.
for (TouchExplorationStateChangeListener listener :mTouchExplorationStateChangeListeners) {
listener.onTouchExplorationStateChanged(isTouchExplorationEnabled);
}
}
/**
* Notifies the registered {@link HighTextContrastChangeListener}s.
*/
private void handleNotifyHighTextContrastStateChanged() {
final boolean isHighTextContrastEnabled;
synchronized (mLock) {
isHighTextContrastEnabled = mIsHighTextContrastEnabled;
}
// Listeners are a final CopyOnWriteArrayList, hence no lock needed.
for (HighTextContrastChangeListener listener : mHighTextContrastStateChangeListeners) {
listener.onHighTextContrastStateChanged(isHighTextContrastEnabled);
}
}
private final class MyHandler extends Handler {
public static final int MSG_NOTIFY_ACCESSIBILITY_STATE_CHANGED = 1;
public static final int MSG_NOTIFY_EXPLORATION_STATE_CHANGED = 2;
public static final int MSG_NOTIFY_HIGH_TEXT_CONTRAST_STATE_CHANGED = 3;
public static final int MSG_SET_STATE = 4;
public MyHandler(Looper looper) {
super(looper, null, false);
}
@Override
public void handleMessage(Message message) {
switch (message.what) {
case MSG_NOTIFY_ACCESSIBILITY_STATE_CHANGED: {
handleNotifyAccessibilityStateChanged();
} break;
case MSG_NOTIFY_EXPLORATION_STATE_CHANGED: {
handleNotifyTouchExplorationStateChanged();
} break;
case MSG_NOTIFY_HIGH_TEXT_CONTRAST_STATE_CHANGED: {
handleNotifyHighTextContrastStateChanged();
} break;
case MSG_SET_STATE: {
// See comment at mClient
final int state = message.arg1;
synchronized (mLock) {
setStateLocked(state);
}
} break;
}
}
}
}
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