@Override
        protected void onDestroy() {

            NotificationManager notificationManager = ((NotificationManager)getSystemService( Context.NOTIFICATION_SERVICE));
            notificationManager.cancelAll();

            super.onDestroy();
        }

public class Notificacion extends Service {
    public Notificacion() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException( "Not yet implemented" );
    }

    private PendingIntent pendingIntent;
    private final static String CHANNEL_ID = "NOTIFICACION";
    private final static int NOTIFICACION_ID = 0;
    private Resources mResources;

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

        createNotificationChannel();
        createNotification();

        mResources = getResources();

    }

    private void createNotificationChannel(){
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            CharSequence name = "Noticacion";
            NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ID, name, NotificationManager.IMPORTANCE_HIGH);
            NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            notificationManager.createNotificationChannel(notificationChannel);
        }
    }

    private void createNotification(){
        NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext(), CHANNEL_ID);

        Intent resultIntent = new Intent(this, MainActivity.class);
    PendingIntent resultPendingIntent = PendingIntent.getActivity(this, 1, resultIntent, PendingIntent.FLAG_ONE_SHOT);

    builder.setSmallIcon(R.drawable.logo);
    builder.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.logo));
    builder.setContentTitle("Notificacion Android");
    builder.setContentText("ESTA ES MI APP");
    builder.setColor( Color.WHITE);
    builder.setPriority(NotificationCompat.PRIORITY_HIGH);
    builder.setDefaults( Notification.DEFAULT_SOUND);
    builder.setContentIntent(resultPendingIntent);


        NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(getApplicationContext());
        notificationManagerCompat.notify(NOTIFICACION_ID, builder.build());
    }
 }