I want a service to run all the time in my application. So I want to restart it even if it is force closed by user. There is definitely a way to do it as apps like facebook are doing it.(Its not done using push notification, facebook restarts its service even if internet is off).
Any help would be appreciated. Thanks!
First of all, it is really very bad pattern to run service forcefully against the user's willingness.
Anyways, you can restart it by using a BroadcastReceiver which handles the broadcast sent from onDestroy() of your service.
StickyService.java
public class StickyService extends Service
{
private static final String TAG = "StickyService";
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e(TAG, "onStartCommand");
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
sendBroadcast(new Intent("YouWillNeverKillMe"));
}
}
RestartServiceReceiver.java
public class RestartServiceReceiver extends BroadcastReceiver
{
private static final String TAG = "RestartServiceReceiver";
@Override
public void onReceive(Context context, Intent intent) {
Log.e(TAG, "onReceive");
context.startService(new Intent(context.getApplicationContext(), StickyService.class));
}
}
Declare the components in manifest file:
<service android:name=".StickyService" >
</service>
<receiver android:name=".RestartServiceReceiver" >
<intent-filter>
<action android:name="YouWillNeverKillMe" >
</action>
</intent-filter>
</receiver>
Start the StickyService in a Component (i.e. Application, Activity, Fragment):
startService(new Intent(this, StickyService.class));
OR
sendBroadcast(new Intent("YouWillNeverKillMe"));
You have to create a sticky service with overriding onTaskRemoved method, where you can set an alarm service to trigger your code again.
public class BackgroundService extends Service {
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_STICKY;
}
@Override
public void onTaskRemoved(Intent rootIntent) {
//create an intent that you want to start again.
Intent intent = new Intent(getApplicationContext(), BackgroundService.class);
PendingIntent pendingIntent = PendingIntent.getService(this, 1, intent, PendingIntent.FLAG_ONE_SHOT);
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime() + 5000, pendingIntent);
super.onTaskRemoved(rootIntent);
}
}
Also in some devices like Xiaomi, Huwaei the app gets force closed once it's removed from recent apps. This is because the manufacturers have task manager features which improve ram/battery performance.
You can check this link for more information: https://stackoverflow.com/a/41360159/2798289
As per the Android document
Starting from Android 3.1, the system's package manager keeps track of applications
that are in a stopped state and provides a means of controlling their launch from
background processes and other applications.
Note that an application's stopped state is not the same as an Activity's stopped
state. The system manages those two stopped states separately.
FLAG_INCLUDE_STOPPED_PACKAGES — Include intent filters of stopped applications in the
list of potential targets to resolve against.
FLAG_EXCLUDE_STOPPED_PACKAGES — Exclude intent filters of stopped applications from the
list of potential targets.
When neither or both of these flags is defined in an intent, the default behavior is to
include filters of stopped applications in the list of potential targets.
Note that the system adds FLAG_EXCLUDE_STOPPED_PACKAGES to all broadcast intents.
It does this to prevent broadcasts from background services from inadvertently or
unnecessarily launching components of stopped applications. A background service
or application can override this behavior by adding the FLAG_INCLUDE_STOPPED_PACKAGES
flag to broadcast intents that should be allowed to activate stopped applications.
On Force stop of app, Android just kill the process ID. No warnings, callbacks are given to service/activities. As per the Android document, When the app is killed there are chances that it calls onPause().
When I tried in my app, even onPause() was not called. I think the only way is use to FLAG_INCLUDE_STOPPED_PACKAGES intent flag and send it from another app
If I understand correctly, then actually this is not possible, Android feature to force close application was designed to allow user to get rid of unwanted applications, so it disallows any activities from it until user again starts any of its Activity.
Whenever a service is killed, its onDestroy method is always called.
Its better to use a BroadcastReceiver to start your service when it is killed.
Here is a sample code illustrating its implementation:-
@Override
public void onDestroy() {
Intent in = new Intent();
in.setAction("StartkilledService");
sendBroadcast(in);
Log.d("debug", "Service Killed");
}
Then register a receiver in AndroidManifest.xml:-
<receiver android:name=".app.ServiceDestroyReceiver" >
<intent-filter>
<action android:name="StartKilledService" >
</action>
</intent-filter>
</receiver>
Finally,create a BroadcastReceiver,and start your service in the onReceive method:-
@Override
public void onReceive(Context context, Intent intent) {
Log.d("debug", "ServeiceDestroy onReceive...");
Log.d("debug", "action:" + intent.getAction());
Log.d("debug", "Starting Service");
ServiceManager.startService();
}
Hope this helps.
on the service's startCommand method return START_STICKY. generally it tell the OS to start the service when it is killed.
If the situation allows to use 'root' it's usually possible to implement Humpty-Dumpty paradigm.
Your application (1st) installs another application (2nd, taking APK from assets) and runs the service of the 2nd app. 2nd app's service bind to the 1st app service and rebinds when disconnected. The 1st app does the same.
Sure it will not help when all apps are killed by some Free RAM or similar application but when Android kills either of those two, the other one will restart its counterpart.
The only real solution for keeping services alive ist to call Service.startForeground(...) with a provided Notification. This will be the only valid solution, every other one will be very dependent on how Google will change the behaviour of it's system. With every API update, Google could prevent every other hack.
This also keeps the user aware, that your app is performing some background task which will keep the app alive and the user has to stop this. If you provide the user the ability to stop it is part of your application, though.
void startForeground (int id, Notification notification)
Make this service run in the foreground, supplying the ongoing notification to be shown to the user while in this state. By default services are background, meaning that if the system needs to kill them to reclaim more memory (such as to display a large page in a web browser), they can be killed without too much harm. You can set this flag if killing your service would be disruptive to the user, such as if your service is performing background music playback, so the user would notice if their music stopped playing.
There is a very hacky solution to keep service running even you force stop it. I do not recommend that because it is against user willingness. You can define a broadcast receiver to receive intent with action X. onStartCommand handler of your service, broadcast X (if the service is not started yet). on broadcast receiver upon receipt of X, first start the service, then, sleep for some minutes, and finally re-broadcast X.
I think the only foolproof solution here is to have 2 services in separate processes (android:process="somecustomprocessname" in manifest, in the service entry) that both listen to broadcasts and restart each other, because currently the UI doesn't let users kill multiple processes in one action. You can then set up a pinger thread in each service that checks if the other service is running every 100 milliseconds or so, and if not, attempts to restart it. But this is starting to look more and more like malware...
