2个基于活动的片段的片段生命周期

Question

I have 2 activity based fragments, an activity that holds a List Fragment and when an item is being click it will trigger the other activity that holds the other fragment (lets call it DisplayFragment) in order to display the necessary data. Upon clicking the an item on the List Fragment the system calls these methods before creating/displaying the other fragment.

List Fragment:

OnPause() -> onStop()

which is right according to the life cycle chart of fragments, but when I press the back button the system call the following methods:

(DisplayFragment) onPause() -> (ListFragment) onDestroyView() -> (ListFragment) onDestroy() 
-> (ListFragment) onCreate() -> (ListFragment) onCreateView() -> (ListFragment) onResume() 
->(DisplayFragment) onStop() -> (ListFragment) onDestroyView() -> (ListFragment) onDestroy()

I was confused why does the system calls the methods on this order. Why does the (ListFragment) onDestroyView() was called after the onPause of the other was executed, why not destroying everything first before creating or calling a new fragment?

Answer 1

This may have to do with the activities lifecycle since the fragment inherits its lifecycle calls from its parent activity. Look into the activity lifecycle and you'll probably see the same thing. After your detail fragment is done, your probably finishing your activity so thats why you get those calls when resuming your previous activity.

If this isn't desired, just use 1 activity and use FragmentTransaction to switch them out.