fragment-overview

public class SomeFragment extends Fragment {
    ThingsAdapter adapter;
    FragmentActivity listener;

    // This event fires 1st, before creation of fragment or any views
    // The onAttach method is called when the Fragment instance is associated with an Activity. 
    // This does not mean the Activity is fully initialized.
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof Activity){
            this.listener = (FragmentActivity) context;
        }
    }

    // This event fires 2nd, before views are created for the fragment
    // The onCreate method is called when the Fragment instance is being created, or re-created.
    // Use onCreate for any standard setup that does not require the activity to be fully created
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ArrayList<Thing> things = new ArrayList<Thing>();
        adapter = new ThingsAdapter(getActivity(), things);
    }

    // The onCreateView method is called when Fragment should create its View object hierarchy,
    // either dynamically or via XML layout inflation. 
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_some, parent, false);
    }

    // This event is triggered soon after onCreateView().
    // onViewCreated() is only called if the view returned from onCreateView() is non-null.
    // Any view setup should occur here.  E.g., view lookups and attaching view listeners.
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        ListView lv = (ListView) view.findViewById(R.id.lvSome);
        lv.setAdapter(adapter);
    }

    // This method is called when the fragment is no longer connected to the Activity
    // Any references saved in onAttach should be nulled out here to prevent memory leaks. 
    @Override
    public void onDetach() {
        super.onDetach();
        this.listener = null;
    }

    // This method is called after the parent Activity's onCreate() method has completed.
    // Accessing the view hierarchy of the parent activity must be done in the onActivityCreated.
    // At this point, it is safe to search for activity View objects by their ID, for example.
    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }
}
프래그먼트 개요

학습목표

1. 프래그먼트(Fragment) 란?

2. 액티비티 vs 프래그먼트 비교

3. 프래그먼트 수명주기
