* The service is meant to be called via {@code ProcessingService.addTask}, * which takes care of starting the service and enqueueing the * {@code ProcessingTask} task: * *
* {@code
* ProcessingTask task = new MyProcessingTask(...);
* ProcessingService.addTask(task);
* }
*
*/
public class ProcessingService extends Service implements ProgressListener {
/**
* Class used to receive broadcast and control the service accordingly.
*/
public class ServiceController extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction() == ACTION_PAUSE_PROCESSING_SERVICE) {
ProcessingService.this.pause();
} else if (intent.getAction() == ACTION_RESUME_PROCESSING_SERVICE) {
ProcessingService.this.resume();
}
}
}
private static final Log.Tag TAG = new Log.Tag("ProcessingService");
private static final int THREAD_PRIORITY = Process.THREAD_PRIORITY_BACKGROUND;
private static final int CAMERA_NOTIFICATION_ID = 2;
private Notification.Builder mNotificationBuilder;
private NotificationManager mNotificationManager;
/** Sending this broadcast intent will cause the processing to pause. */
public static final String ACTION_PAUSE_PROCESSING_SERVICE =
"com.android.camera.processing.PAUSE";
/**
* Sending this broadcast intent will cause the processing to resume after
* it has been paused.
*/
public static final String ACTION_RESUME_PROCESSING_SERVICE =
"com.android.camera.processing.RESUME";
private WakeLock mWakeLock;
private final ServiceController mServiceController = new ServiceController();
/** Manages the capture session. */
private CaptureSessionManager mSessionManager;
private ProcessingServiceManager mProcessingServiceManager;
private Thread mProcessingThread;
private volatile boolean mPaused = false;
private ProcessingTask mCurrentTask;
private final Lock mSuspendStatusLock = new ReentrantLock();
@Override
public void onCreate() {
mProcessingServiceManager = ProcessingServiceManager.instance();
mSessionManager = getServices().getCaptureSessionManager();
// Keep CPU awake while allowing screen and keyboard to switch off.
PowerManager powerManager = AndroidServices.instance().providePowerManager();
mWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG.toString());
mWakeLock.acquire();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(ACTION_PAUSE_PROCESSING_SERVICE);
intentFilter.addAction(ACTION_RESUME_PROCESSING_SERVICE);
LocalBroadcastManager.getInstance(this).registerReceiver(mServiceController, intentFilter);
mNotificationBuilder = createInProgressNotificationBuilder();
mNotificationManager = AndroidServices.instance().provideNotificationManager();
}
@Override
public void onDestroy() {
Log.d(TAG, "Shutting down");
// TODO: Cancel session in progress...
// Unlock the power manager, i.e. let power management kick in if
// needed.
if (mWakeLock.isHeld()) {
mWakeLock.release();
}
LocalBroadcastManager.getInstance(this).unregisterReceiver(mServiceController);
stopForeground(true);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d(TAG, "Starting in foreground.");
// We need to start this service in foreground so that it's not getting
// killed easily when memory pressure is building up.
startForeground(CAMERA_NOTIFICATION_ID, mNotificationBuilder.build());
asyncProcessAllTasksAndShutdown();
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
// We don't provide binding, so return null.
return null;
}
private void pause() {
Log.d(TAG, "Pausing");
try {
mSuspendStatusLock.lock();
mPaused = true;
if (mCurrentTask != null) {
mCurrentTask.suspend();
}
} finally {
mSuspendStatusLock.unlock();
}
}
private void resume() {
Log.d(TAG, "Resuming");
try {
mSuspendStatusLock.lock();
mPaused = false;
if (mCurrentTask != null) {
mCurrentTask.resume();
}
} finally {
mSuspendStatusLock.unlock();
}
}
/**
* Starts a thread to process all tasks. When no more tasks are in the
* queue, it exits the thread and shuts down the service.
*/
private void asyncProcessAllTasksAndShutdown() {
if (mProcessingThread != null) {
return;
}
mProcessingThread = new Thread("CameraProcessingThread") {
@Override
public void run() {
// Set the thread priority
android.os.Process.setThreadPriority(THREAD_PRIORITY);
ProcessingTask task;
while ((task = mProcessingServiceManager.popNextSession()) != null) {
mCurrentTask = task;
try {
mSuspendStatusLock.lock();
if (mPaused) {
mCurrentTask.suspend();
}
} finally {
mSuspendStatusLock.unlock();
}
processAndNotify(task);
}
stopSelf();
}
};
mProcessingThread.start();
}
/**
* Processes a {@code ProcessingTask} and updates the notification bar.
*/
void processAndNotify(ProcessingTask task) {
if (task == null) {
Log.e(TAG, "Reference to ProcessingTask is null");
return;
}
CaptureSession session = task.getSession();
// TODO: Get rid of this null check. There should not be a task without
// a session.
if (session == null) {
// TODO: Timestamp is not required right now, refactor this to make it clearer.
session = mSessionManager.createNewSession(task.getName(), 0, task.getLocation());
}
resetNotification();
// Adding the listener also causes it to get called for the session's
// current status message and percent completed.
session.addProgressListener(this);
System.gc();
Log.d(TAG, "Processing start");
task.process(this, getServices(), session);
Log.d(TAG, "Processing done");
}
private void resetNotification() {
mNotificationBuilder.setContentText("…").setProgress(100, 0, false);
postNotification();
}
/**
* Returns the common camera services.
*/
private CameraServices getServices() {
return CameraServicesImpl.instance();
}
private void postNotification() {
mNotificationManager.notify(CAMERA_NOTIFICATION_ID, mNotificationBuilder.build());
}
/**
* Creates a notification to indicate that a computation is in progress.
*/
private Notification.Builder createInProgressNotificationBuilder() {
return new Notification.Builder(this)
.setSmallIcon(R.drawable.ic_notification)
.setWhen(System.currentTimeMillis())
.setOngoing(true)
.setContentTitle(this.getText(R.string.app_name));
}
@Override
public void onProgressChanged(int progress) {
mNotificationBuilder.setProgress(100, progress, false);
postNotification();
}
@Override
public void onStatusMessageChanged(int messageId) {
mNotificationBuilder.setContentText(messageId > 0 ? getString(messageId) : "");
postNotification();
}
}