Unable to start receiver : Not allowed to start service Intent ; App is in background

Question

So I made an app that upon a button click sets up a repeating task using an Alarm Manager.

In on create:

Intent alarmIntent = new Intent(this, AlarmReceiver.class);
servicePendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);

On the button click:

alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);

    firingCal= Calendar.getInstance();
    firingCal.setTimeInMillis(System.currentTimeMillis());
    firingCal.set(Calendar.HOUR_OF_DAY, 1); // At the hour you want to fire the alarm
    firingCal.set(Calendar.MINUTE, 47); // alarm minute
    firingCal.set(Calendar.SECOND, 0); // and alarm second
    long intendedTime = firingCal.getTimeInMillis();

    long interval = 1000 * 60 * 1;


    alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, intendedTime, interval, servicePendingIntent);

In the AlarmReceiver class:

public void onReceive(Context context, Intent intent) {

    Intent myIntent = new Intent(context, WallpaperService.class);

    context.startService(myIntent);
    Log.d(TAG,"Am apelat serviciul");

    context.stopService(myIntent);

}

And in the WallpaperService class I just make a get request and set an wallpaper.

public class WallpaperService extends Service {

String requestLink="";
boolean requestFinished = false;
public final String TAG = "Service";
public  static int SERVICE_ID = 1;

@Override
public void onCreate() {
    super.onCreate();
    Log.d(TAG,"Wallpaper Service started");
    Toast.makeText(WallpaperService.this,"Service started",Toast.LENGTH_LONG);
}

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

    Log.d(TAG,"In onStartCommand");
    taskToBeRepeated();
    stopSelf();

    return START_STICKY;
}
.....
}

And the behaviour is that when I start the app and I click the button everything works well the first time the Alarm Manager fires ( With the app in the background). The second time the receiver gets triggered I get the error in the tile. To be more specific :

java.lang.RuntimeException: Unable to start receiver com.example.dailywallpaper.AlarmReceiver: java.lang.IllegalStateException: Not allowed to start service Intent { cmp=com.example.dailywallpaper/.WallpaperService }: app is in background uid UidRecord{3e313bf u0a357 RCVR bg:+1m21s273ms idle change:uncached procs:1 seq(0,0,0)}

What seems to be the problem ? And why is working the first time and then it gives the error? How can I fix it ?

Answer 1

you need to read android official documentation about the policy of using background service or alarms in android 8 and above and adapt your app with this limitations.

I suggest you to read this two articles very carefully :

https://developer.android.com/guide/components/services

https://developer.android.com/about/versions/oreo/background