I am trying to program my notification to RESUME my app, instead of simply starting a new instance of my app... I am basically looking for it to do the same thing as when th
you need to set your flags
notification.flags = Notification.FLAG_ONGOING_EVENT | Notification.FLAG_NO_CLEAR;
notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
Also, if you never ever want there to be a duplicate activity give it this attribute in the manifest
android:launchMode="singleTask"
Selected answer didn't work for me, but if anyone else if viewing this, this did work for me: Resume application and stack from notification