// Cancel older notification with same id,
NotificationManager notificationMgr = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
notificationMgr.cancel(CALL_NOTIFY_ID);// any constant value
// Create Pending Intent,
Intent notificationIntent = null;
PendingIntent contentIntent = null;
notificationIntent = new Intent (context, YourActivityName);
contentIntent = PendingIntent.getActivity(context, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
// Notification builder
builder = new NotificationCompat.Builder(context);
builder.setContentText("Ongoing Notification..");
builder.setContentTitle("ongoing notification sample");
builder.setSmallIcon(R.drawable.notification_icon);
builder.setUsesChronometer(true);
builder.setDefaults(Notification.DEFAULT_LIGHTS);
builder.setContentIntent(contentIntent);
builder.setOngoing(true);
// Add action button in the notification
Intent intent = new Intent("action.name");
PendingIntent pIntent = PendingIntent.getBroadcast(context, 1, intent, 0);
builder.addAction(R.drawable.action_button_icon, "Action button name",pIntent);
// Notify using notificationMgr
Notification finalNotification = builder.build();
notificationMgr.notify(CALL_NOTIFY_ID, finalNotification);
Register a broadcast receiver for the same action to handle action button click event.