Notification

Three things needed for a notification on the top.
1. a notification manager manage everything.
2. a notification itself has the icon, sounds, and ticker.
3. a Intent that is going to run when an user click the notification.

notificationManager = (NotificationManager) this.getSystemService(NOTIFICATION_SERVICE);
  notification = new Notification();
  notification.icon = R.drawable.icon;
  notification.defaults = Notification.DEFAULT_SOUND;
  notification.tickerText = "Bu.......";
  notification.flags |= Notification.FLAG_AUTO_CANCEL;

  Intent notifyIntent = new Intent(getBaseContext(), ServiceDemo.class);
  PendingIntent PendTntent = PendingIntent.getActivity(this, 0, notifyIntent, android.content.Intent.FLAG_ACTIVITY_NEW_TASK);
  notification.setLatestEventInfo(this,"Title","Check the latest update",PendTntent);

Once you have everything ready, you can use the following code to trigger the notification.

notificationManager.notify(0, notification);