How an Android service update a TextView continuously?

Question

I want to create a service which will update a Textview continuously, even if I run an another app. The service will be stopped if I push the stop button. In the following code, I use the combination of the service and the BroadcastReceiver, but the service doesn't update the TextView if I change the application.

Code:

Service

public class ChronometerService extends Service
{
    public static final String BROADCAST_ACTION = "com.example.test";
    private final Handler handler = new Handler();
    private Intent intent = null;
    int counter = 0;

    @Override
    public void onCreate()
    {
        super.onCreate();

        intent = new Intent( BROADCAST_ACTION );
    }

    @Override
    public void onStart( Intent intent, int startId )
    {
        //handler.removeCallbacks( sendUpdatesToUI );
        handler.postDelayed( sendUpdatesToUI, 1000 );
    }


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


    private Runnable sendUpdatesToUI = new Runnable()
    {
        @Override
        public void run() 
        {
            DisplayLoggingInfo();
            handler.postDelayed( this, 1000 );
        }
    };


    private void DisplayLoggingInfo()
    {
        counter += 1;
        //chrono.start();
        intent.putExtra( "TIME", String.valueOf(counter) );
        sendBroadcast( intent );
    }


    @Override
    public void onDestroy()
    {   
        //chrono.stop();
        //chrono.setBase( SystemClock.elapsedRealtime() );
        handler.removeCallbacks( sendUpdatesToUI );     
        super.onDestroy();
    }       
}

Activity

public class MainActivity extends Activity 
{
    public static TextView chronometer1 = null;
    private Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        intent = new Intent( MainActivity.this, ChronometerService.class );
    }


    private BroadcastReceiver broadcastReceiver = new BroadcastReceiver()
    {
        @Override
        public void onReceive( Context context, Intent intent )
        {
            updateUI( intent );       
        }
    };

    private void updateUI( Intent intent )
    {
        String time = intent.getStringExtra( "TIME" );
        chronometer1 = ( TextView ) findViewById( R.id.chronometer1 );
        chronometer1.setText( time );
    }

    public void start( View v )
    {
        startService( intent );
        registerReceiver(broadcastReceiver, new IntentFilter( ChronometerService.BROADCAST_ACTION ) );
    }

    public void stop( View v )
    {
        unregisterReceiver( broadcastReceiver );
        stopService( intent );
    }
}

Answer 1

I found the answer: When the service is running and I do not want it to be killed by the OS, I have to use the startForeground(int id, Notification notification) method.

When the service finishes whatever is doing and can be killed by the OS, call stopForeground(boolean removeNotification). "startForeground" requires a notification as argument because every foreground service must display a notification so the user realizes about it.

Also helps to set in the service declaration in the manifest file the attribute:

android:process=":some name here"