Serivces on Android rebooting variables

Question

Me developing a test application in which a Service is running in Background and is sending notifications to your phone every 10 seconds. To improve the test I created a counter that increases with each notification sent. The Service works almost perfectly, however, if I open and close the APP the counter restarts to 1 and I have no idea why. I talked about closing the APP and not minimizing, there is a big difference between minimize the APP and close, if I minimize remains normal but if I close it yes the counter restarts.

Service class:

public class BackgroundService extends Service {

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

    public sattic int j = 1;


   @Override
   public void onCreate() {
        new Thread() {
            @Override
            public void run() {
                while (true) {
                    NotificationCompat.Builder builder = new NotificationCompat.Builder(BackgroundService.this)
                            .setContentTitle("Notificação: " + j)
                            .setContentText("Texto da notificação: " + j)
                            .setTicker("Texto que aparece ao receber a notificação.")
                            .setBadgeIconType(R.drawable.error)
                            .setSmallIcon(R.drawable.help)
                            .setAutoCancel(true);

                    NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
                    notificationManager.notify(1, builder.build());
                     j++;
                    try {
                        Thread.sleep(10000);
                    } catch (Throwable e) {
                        Log.create(e);
                    }
                }
            }
        }.start();
   }
}

Main class:

     public class MainActivity extends AppCompatActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            startService(new Intent(getBaseContext(), BackgroundService.class));
        }
}

In short, if I open the app the counter and the notifications work normally, however if I close the application the counter restarts from 1 (the notifications keep appearing but the counter restarts). I talked about closing the APP and not minimizing, there is a big difference between minimize the APP and close, if I minimize remains normal but if I close it yes the counter restarts.

I already tried to put the counter variable inside the Thread but it didn’t work it restarts the same way.

Answer 1

it is normal to restart, every time the service is activated, it will create a new instance of Service with the default values of the class, if you want to make a counter with the old value, I suggest you store the current value every time you finish running Service and access this value when you start Service

Here are some options of Data Storage on Android to do this

https://developer.android.com/guide/topics/data/data-storage?hl=pt-br