I wrote a simple Android App that show a custom Notification like this:
Context context = getApplicationContext();
NotificationManager manager = (N
Problem: You are sending the same request code for your pending intens. Change this.
Solution: Set global variable int UNIQUE_INT_PER_CALL =0 and when you create pendingIntent call like below.
PendingIntent contentIntent = PendingIntent.getActivity(context, UNIQUE_INT_PER_CALL, notificationIntent, 0);
UNIQUE_INT_PER_CALL++; // to increment.