/*
* 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.accessibilityservice.AccessibilityServiceInfo;
import android.content.Context;
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.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
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;
static final Object sInstanceSync = new Object();
private static AccessibilityManager sInstance;
private static final int DO_SET_STATE = 10;
final IAccessibilityManager mService;
final Handler mHandler;
boolean mIsEnabled;
boolean mIsTouchExplorationEnabled;
final CopyOnWriteArrayList<AccessibilityStateChangeListener> mAccessibilityStateChangeListeners =
new CopyOnWriteArrayList<AccessibilityStateChangeListener>();
/**
* 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 AccessibilityManager#addAccessibilityStateChangeListener
* addAccessibilityStateChangeListener()}.
*/
public interface AccessibilityStateChangeListener {
/**
* Called back on change in the accessibility state.
*
* @param enabled Whether accessibility is enabled.
*/
public void onAccessibilityStateChanged(boolean enabled);
}
final IAccessibilityManagerClient.Stub mClient = new IAccessibilityManagerClient.Stub() {
public void setState(int state) {
mHandler.obtainMessage(DO_SET_STATE, state, 0).sendToTarget();
}
};
class MyHandler extends Handler {
MyHandler(Looper mainLooper) {
super(mainLooper);
}
@Override
public void handleMessage(Message message) {
switch (message.what) {
case DO_SET_STATE :
setState(message.arg1);
return;
default :
Log.w(LOG_TAG, "Unknown message type: " + message.what);
}
}
}
/**
* Get an AccessibilityManager instance (create one if necessary).
*
* @hide
*/
public static AccessibilityManager getInstance(Context context) {
synchronized (sInstanceSync) {
if (sInstance == null) {
IBinder iBinder = ServiceManager.getService(Context.ACCESSIBILITY_SERVICE);
IAccessibilityManager service = IAccessibilityManager.Stub.asInterface(iBinder);
sInstance = new AccessibilityManager(context, service);
}
}
return sInstance;
}
/**
* Create an instance.
*
* @param context A {@link Context}.
* @param service An interface to the backing service.
*
* @hide
*/
public AccessibilityManager(Context context, IAccessibilityManager service) {
mHandler = new MyHandler(context.getMainLooper());
mService = service;
try {
final int stateFlags = mService.addClient(mClient);
setState(stateFlags);
} catch (RemoteException re) {
Log.e(LOG_TAG, "AccessibilityManagerService is dead", re);
}
}
/**
* Returns if the accessibility in the system is enabled.
*
* @return True if accessibility is enabled, false otherwise.
*/
public boolean isEnabled() {
synchronized (mHandler) {
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 (mHandler) {
return mIsTouchExplorationEnabled;
}
}
/**
* Returns the client interface this instance registers in
* the centralized accessibility manager service.
*
* @return The client.
*
* @hide
*/
public IAccessibilityManagerClient getClient() {
return (IAccessibilityManagerClient) mClient.asBinder();
}
/**
* Sends an {@link AccessibilityEvent}.
*
* @param event The event to send.
*
* @throws IllegalStateException if accessibility is not enabled.
*/
public void sendAccessibilityEvent(AccessibilityEvent event) {
if (!mIsEnabled) {
throw new IllegalStateException("Accessibility off. Did you forget to check that?");
}
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 = mService.sendAccessibilityEvent(event);
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() {
if (!mIsEnabled) {
throw new IllegalStateException("Accessibility off. Did you forget to check that?");
}
try {
mService.interrupt();
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<ServiceInfo>();
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() {
List<AccessibilityServiceInfo> services = null;
try {
services = mService.getInstalledAccessibilityServiceList();
if (DEBUG) {
Log.i(LOG_TAG, "Installed AccessibilityServices " + services);
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while obtaining the installed AccessibilityServices. ", re);
}
return Collections.unmodifiableList(services);
}
/**
* 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
*/
public List<AccessibilityServiceInfo> getEnabledAccessibilityServiceList(
int feedbackTypeFlags) {
List<AccessibilityServiceInfo> services = null;
try {
services = mService.getEnabledAccessibilityServiceList(feedbackTypeFlags);
if (DEBUG) {
Log.i(LOG_TAG, "Installed AccessibilityServices " + services);
}
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while obtaining the installed AccessibilityServices. ", re);
}
return Collections.unmodifiableList(services);
}
/**
* 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(
AccessibilityStateChangeListener listener) {
return mAccessibilityStateChangeListeners.add(listener);
}
/**
* Unregisters an {@link AccessibilityStateChangeListener}.
*
* @param listener The listener.
* @return True if successfully unregistered.
*/
public boolean removeAccessibilityStateChangeListener(
AccessibilityStateChangeListener listener) {
return mAccessibilityStateChangeListeners.remove(listener);
}
/**
* Sets the current state.
*
* @param stateFlags The state flags.
*/
private void setState(int stateFlags) {
final boolean accessibilityEnabled = (stateFlags & STATE_FLAG_ACCESSIBILITY_ENABLED) != 0;
setAccessibilityState(accessibilityEnabled);
mIsTouchExplorationEnabled = (stateFlags & STATE_FLAG_TOUCH_EXPLORATION_ENABLED) != 0;
}
/**
* Sets the enabled state.
*
* @param isEnabled The accessibility state.
*/
private void setAccessibilityState(boolean isEnabled) {
synchronized (mHandler) {
if (isEnabled != mIsEnabled) {
mIsEnabled = isEnabled;
notifyAccessibilityStateChanged();
}
}
}
/**
* Notifies the registered {@link AccessibilityStateChangeListener}s.
*/
private void notifyAccessibilityStateChanged() {
final int listenerCount = mAccessibilityStateChangeListeners.size();
for (int i = 0; i < listenerCount; i++) {
mAccessibilityStateChangeListeners.get(i).onAccessibilityStateChanged(mIsEnabled);
}
}
/**
* 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) {
try {
return mService.addAccessibilityInteractionConnection(windowToken, connection);
} 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) {
try {
mService.removeAccessibilityInteractionConnection(windowToken);
} catch (RemoteException re) {
Log.e(LOG_TAG, "Error while removing an accessibility interaction connection. ", re);
}
}
}