Hmm, that is strange… On Android, there are four lifecycle methods of activity:
onStart, onResume, onPause and onDestroy (i’m not sure about last one name), and each and every one of them is called when activity is changing it’s lifecylce.
The concept of quit is present as onDestroy method of activity. As for lacking this the only mobile platform which is missing this is propably iOS, which does not cover any events for shutting down, only pause as you said.