Android Service needs to run always (Never pause or stop)

“Is it possible to run this service always as when the application pause and anything else?”

Yes.

1. In the service onStartCommand method return START_STICKY.

   public int onStartCommand(Intent intent, int flags, int startId) {
           return START_STICKY;
   }
   

2. Start the service in the background using startService(MyService) so that it always stays active regardless of the number of bound clients.

   Intent intent = new Intent(this, PowerMeterService.class);
   startService(intent);
   

3. Create the binder.

   public class MyBinder extends Binder {
           public MyService getService() {
                   return MyService.this;
           }
   }
   

4. Define a service connection.

   private ServiceConnection m_serviceConnection = new ServiceConnection() {
           public void onServiceConnected(ComponentName className, IBinder service) {
                   m_service = ((MyService.MyBinder)service).getService();
           }
   
           public void onServiceDisconnected(ComponentName className) {
                   m_service = null;
           }
   };
   

5. Bind to the service using bindService.

           Intent intent = new Intent(this, MyService.class);
           bindService(intent, m_serviceConnection, BIND_AUTO_CREATE);
   

6. For your service you may want a notification to launch the appropriate activity once it has been closed.

   private void addNotification() {
           // create the notification
           Notification.Builder m_notificationBuilder = new Notification.Builder(this)
                   .setContentTitle(getText(R.string.service_name))
                   .setContentText(getResources().getText(R.string.service_status_monitor))
                   .setSmallIcon(R.drawable.notification_small_icon);
   
           // create the pending intent and add to the notification
           Intent intent = new Intent(this, MyService.class);
           PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
           m_notificationBuilder.setContentIntent(pendingIntent);
   
           // send the notification
           m_notificationManager.notify(NOTIFICATION_ID, m_notificationBuilder.build());
   }
   

7. You need to modify the manifest to launch the activity in single top mode.

             android:launchMode="singleTop"
   

8. Note that if the system needs the resources and your service is not very active it may be killed. If this is unacceptable bring the service to the foreground using startForeground.

           startForeground(NOTIFICATION_ID, m_notificationBuilder.build());