Android™ How to Program, Second Edition

ContactListFragment Overridden Methods onAttach and onDetach

Class ContactListFragment overrides Fragment lifecycle methods onAttach and onDetach (Fig. 8.26) to set instance variable listener. In this app, listener refers to the host Activity (line 42) when the ContactListFragment is attached and is set to null (line 50) when the ContactListFragment is detached.

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37      // set ContactListFragmentListener when fragment attached38      @Override39      public void onAttach(Activity activity)40      {41         super.onAttach(activity);42         listener = (ContactListFragmentListener) activity;43      }44 45      // remove ContactListFragmentListener when Fragment detached46      @Override47      public void onDetach() ...