应用程序被杀死然后重新启动时，Android服务（在其自己的线程中）死亡

Question

I've been struggling with this question for weeks now. I'm fairly new to Android, hopefully you can give me a hand.

I have this service which runs on a separate thread than the app's. Essentially, the user instructs it to start, and it should stay alive either until the user tells it to stop or until it has served its purpose - it schedules its own destruction (stop) when needed. The service needs to stay alive as it holds important priority-related information, so I can't simply turn to the alarm manager to revive it when needed - though I do use alarm manager for other purposes. I'm having two problems:

• First of all, when the user closes the application (by holding the middle button and close the app) the service is destroyed, which means, I lose my data (I'm assuming it gets destroyed as it reboots automatically).

• Secondly, it restarts itself, thus causing the data to be re-loaded hence, I lose the data.

As for the activity, its binding to the server through:

private void startService() {
    startService(new Intent(this, CES.class));
    bindService(new Intent(this, CES.class), mConnection, 0);
}

Finally, the relevant (or at least the ones I find relevant) methods in the Service:

private final IBinder mBinder = new ICESInterface.Stub() { ..... }
@Override
public void onCreate() {
//keeps being called thus I lose my data }
@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    return super.onStartCommand(intent,flags,startId);
    //return START_STICKY;
}

Let me know if there is more data/information you need.

Answer 1

By returing a binder in onBind you are creating a bound service, which means it is "bound" to your app. This means that it get's destroyed when you app does, that explains the home button destroy. You should be returning null for a background service.

@Override
public void onCreate() {
//keeps being called thus I lose my data
 }
@Override
public IBinder onBind(Intent intent) {
    return null;
}

You should start your service with START_STICKY flag, so that if the OS destroys your service when running low on resources, it will later recreate it.

Prior to destroying your service, Android will call public void onLowMemory() , there save any data you need so that when it restarts your service, you will be able to do your task again.

EDIT: As per your comment, you would like a service that is running in the background and also allows binding. You can do that if you call the startService() method before any bindService() calls are made... this will effectively make your service a started service instead of bound. In that case you are able to return a IBInder and bind to it.

There is a really, really good article HERE