notification led doesn't work

Question

notification.flags |= Notification.FLAG_SHOW_LIGHTS;
notification.ledARGB = Color.BLUE;
notification.ledOnMS = 1000; 
notification.ledOffMS = 1000;

notification.flags |= Notification.FLAG_ONGOING_EVENT;
notificationManager.notify(notifyId, notification);

the code work in an app, but doesn't work in another. The led doesn't flash.
Any answer will be appreciated.

Answer 1

sorry for my careless, the reaseon is this one line code:

notification.defaults = Notification.DEFAULT_ALL;

it means that all the setting, include Light, Sound, Vibration, all follow the system setting.

because of this, this code doesn't work.

notification.flags |= Notification.FLAG_SHOW_LIGHTS;
notification.ledARGB = Color.BLUE;
notification.ledOnMS = 1000; 
notification.ledOffMS = 1000;