cannot find symbol class NotificationManagerCompat
问题 I am trying to build a notification method that would result in a notification appearing on the locked screen when a particular beacon is detected. My understanding is that I need to include .setVisibility(0) in the following code: public void showNotification(Beacon beacon) { Resources r = getResources(); int random = (int)System.currentTimeMillis(); Notification notification = new NotificationCompat.Builder(this) .setSmallIcon(android.R.drawable.ic_popup_reminder) .setContentTitle("Beacons