How to remove notification from notification bar programmatically in android?

I believe the most RECENT and UPDATED way of doing (Kotlin and Java) this should be done as:

NotificationManagerCompat.from(context).cancel(NOTIFICATION_ID)

Or to cancel all notifications is:

NotificationManagerCompat.from(context).cancelAll()

Made for AndroidX or Support Libraries.

Maybe try this :

NotificationManager notificationManager = (NotificationManager) getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.cancel(NOTIFICATION_ID);

OR, you can also do this to cancel all notifications in given context:

notificationManager.cancelAll();

See this link to the documentation : NotificationManager

Notifications remain visible until one of the following happens:

The user dismisses the notification either individually or by using "Clear All" (if the notification can be cleared). The user clicks the notification, and you called setAutoCancel() when you created the notification. You call cancel() for a specific notification ID. This method also deletes ongoing notifications. You call cancelAll(), which removes all of the notifications you previously issued. If you set a timeout when creating a notification using setTimeoutAfter(), the system cancels the notification after the specified duration elapses. If required, you can cancel a notification before the specified timeout duration elapse

public void cancelNotification() {

    String ns = NOTIFICATION_SERVICE;
    NotificationManager nMgr = (NotificationManager) getActivity().getApplicationContext().getSystemService(ns);
    nMgr.cancel(NOTIFICATION_ID);
}