Android onResume and onCreate

Question

I have a question regarding the logic of the life cycle of activities:

When I learned Android, setting up an Activity was always done in the onCreate() function. Now when I resume my Activity, there might be stuff to be done in the onResume() that has already been done in onCreate(). But then, why would we not just put all the stuff into onResume()?

Answer 1

why would we not just put all the stuff into onResume()?

Well onCreate() is called when your Activity is created and you need to initialize some very important things of your application like your main layout!.