android - why we can call getActivity() in onCreateView which run before onActivityCreated?

Question

I really get confused with Fragment lifecycle, especially for the time to call getActivity(). Sometimes you cannot get Activity by getActivity(). And it always caused some puzzling bugs.
Thank you for anyone can solve the puzzle.

Answer 1

getActivity() can be null while your fragment is in process of preparation and about to be ready.

The fragment life cycle is bound to callback methods. These method will be called somewhere in time while fragment is preparing.

• Fragment.onActivityCreated(Bundle) is the place when the fragment activity will not be null, i.e. getActivity() will be a valid instance. It happens after onCreateView() though

Your safest bet for activity existence is:

• Fragment.onViewCreated(View, Bundle)
• Fragment.onStart()