Android: keeping a background service alive (preve

Question

I have a service that is defined as:

public class SleepAccelerometerService extends Service implements SensorEventListener

Essentially, I am making an app that monitors accelerometer activity for various reasons while the user sleeps with his or her phone/device on the bed. This is a long-running service that MUST NOT be killed during the night. Depending on how many background apps and periodic processes occur during the night, android sometimes kills off my process, thereby ending my service. Example:

10-04 03:27:41.673: INFO/ActivityManager(1269): Process com.androsz.electricsleep (pid 16223) has died.
10-04 03:27:41.681: INFO/WindowManager(1269): WIN DEATH: Window{45509f98 com.androsz.electricsleep/com.androsz.electricsleep.ui.SleepActivity paused=false}

I do not want to force the user to have 'SleepActivity' or some other activity in my app as the foreground. I can't have my service run periodically, because it is constantly intercepting onSensorChanged.

Any tips? source code is here: http://code.google.com/p/electricsleep/

Answer 1

When you bind your Service to Activity with BIND_AUTO_CREATE your service is being killed just after your Activity is Destroyed and unbound. It does not depend on how you've implemented your Services unBind method it will be still killed.

The other way is to start your Service with startService method from your Activity. This way even if your Activity is destroyed your service won't be destroyed or even paused but you have to pause/destroy it by yourself with stopSelf/stopService when appropriate.

Answer 2

For Android 2.0 or later you can use the startForeground() method to start your Service in the foreground.

The documentation says the following:

A started service can use the startForeground(int, Notification) API to put the service in a foreground state, where the system considers it to be something the user is actively aware of and thus not a candidate for killing when low on memory. (It is still theoretically possible for the service to be killed under extreme memory pressure from the current foreground application, but in practice this should not be a concern.)

The is primarily intended for when killing the service would be disruptive to the user, e.g. killing a music player service would stop music playing.

You'll need to supply a Notification to the method which is displayed in the Notifications Bar in the Ongoing section.

Answer 3

I'm working on an app and face issue of killing my service by on app kill. I researched on google and found that I have to make it foreground. following is the code:

public class UpdateLocationAndPrayerTimes extends Service {

 Context context;
@Override
public void onCreate() {
    super.onCreate();
    context = this;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    StartForground();
    return START_STICKY;
}

@Override
public void onDestroy() {


    super.onDestroy();
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}


private void StartForground() {
    LocationChangeDetector locationChangeDetector = new LocationChangeDetector(context);
    locationChangeDetector.getLatAndLong();
    Notification notification = new NotificationCompat.Builder(this)
            .setOngoing(false)
            .setSmallIcon(android.R.color.transparent)

            //.setSmallIcon(R.drawable.picture)
            .build();
    startForeground(101,  notification);

    }
}

hops that it may helps!!!!

Answer 4

Keep your service footprint small, this reduces the probability of Android closing your application. You can't prevent it from being killed because if you could then people could easily create persistent spyware

Answer 5

I had a similar issue. On some devices after a while Android kills my service and even startForeground() does not help. And my customer does not like this issue. My solution is to use AlarmManager class to make sure that the service is running when it's necessary. I use AlarmManager to create a kind of watchdog timer. It checks from time to time if the service should be running and restart it. Also I use SharedPreferences to keep the flag whether the service should be running.

Creating/dismissing my watchdog timer:

void setServiceWatchdogTimer(boolean set, int timeout)
{
    Intent intent;
    PendingIntent alarmIntent;
    intent = new Intent(); // forms and creates appropriate Intent and pass it to AlarmManager
    intent.setAction(ACTION_WATCHDOG_OF_SERVICE);
    intent.setClass(this, WatchDogServiceReceiver.class);
    alarmIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    AlarmManager am=(AlarmManager)getSystemService(Context.ALARM_SERVICE);
    if(set)
        am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + timeout, alarmIntent);
    else
        am.cancel(alarmIntent);
}

Receiving and processing the intent from the watchdog timer:

/** this class processes the intent and
 *  checks whether the service should be running
 */
public static class WatchDogServiceReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {

        if(intent.getAction().equals(ACTION_WATCHDOG_OF_SERVICE))
        {
            // check your flag and 
            // restart your service if it's necessary
            setServiceWatchdogTimer(true, 60000*5); // restart the watchdogtimer
        }
    }
}

Indeed I use WakefulBroadcastReceiver instead of BroadcastReceiver. I gave you the code with BroadcastReceiver just to simplify it.

Answer 6

http://developer.android.com/reference/android/content/Context.html#BIND_ABOVE_CLIENT

public static final int BIND_ABOVE_CLIENT -- Added in API level 14

Flag for bindService(Intent, ServiceConnection, int): indicates that the client application binding to this service considers the service to be more important than the app itself. When set, the platform will try to have the out of memory killer kill the app before it kills the service it is bound to, though this is not guaranteed to be the case.

Other flags of the same group are: BIND_ADJUST_WITH_ACTIVITY, BIND_AUTO_CREATE, BIND_IMPORTANT, BIND_NOT_FOREGROUND, BIND_WAIVE_PRIORITY.

Note that the meaning of BIND_AUTO_CREATE has changed in ICS, and old applications that don't specify BIND_AUTO_CREATE will automatically have the flags BIND_WAIVE_PRIORITY and BIND_ADJUST_WITH_ACTIVITY set for them.