Proper use of sub sub fragments with (Child)FragmentManager

You should add SubFragment to Fragment the same way like you add Fragment to Activity. I mean adding Fragment to Activity should look like:

 @Override public void onCreate(Bundle savedInstanceState) {   ....   if (savedInstanceState == null){      //add fragment      mMainFragment = new MainFragment();      FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();      transaction.replace(R.id.fragment_main, mMainFragment);      transaction.commit();   } }

Adding SubFragment to MainFragment should look like:

    public class MainFragment extends Fragment{      @Override      public View onCreateView(LayoutInflater i, ViewGroup c, Bundle savedInstanceState) {           ...        if (savedInstanceState == null){           mSubFragment = new SubFragment();           //add child fragment           getChildFragmentManager()                   .beginTransaction()                   .add(R.id.fragment_sub, mSubFragment, "tag")                   .commit();        }      }    }

or you can add child fragment to Fragment in onCreate method