ListFragment is inflated twice

Question

I have a linear layout (layout_container in skeleton.xml) which is inflated with a ListFragment (menufragment) when the activity is created. Then, when the user performs a click, this layout is replaced with another ListFragment (albumsfragment).

The problem is that when I press the back button, I go back indeed to the menufragment but the list is twice longer because it has been filled up again with the same items. How could I avoid this ?

OnCreate method, inside the Activity:

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.skeleton);

        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();      
        MenuFragment menufragment = new MenuFragment();  
        fragmentTransaction.add(R.id.layout_container, menufragment, "menufragment");      
        fragmentTransaction.commit();

        }

OnClick method, inside the Activity:

  public void OnMenuClick() {

AlbumsFragment albumsfragment = new AlbumsFragment(); 
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.layout_container, albumsfragment, "albumsfragment");
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();

}

My Fragment class code :

public class MenuFragment extends ListFragment{

ArrayList<MenuItem> m_parts = new ArrayList<MenuItem>();

     @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);

            MenuAdapter m_adapter;

            m_parts.add(new MenuItem ("item1"));
            m_parts.add(new MenuItem ("item2"));
            m_parts.add(new MenuItem ("item3"));
            m_parts.add(new MenuItem ("item4"));


            m_adapter = new MenuAdapter(getActivity(), R.layout.menu_row, m_parts);
            setListAdapter(m_adapter);

So each time I go back from AlbumFragment to MenuFragment, the list in MenuFragment grows as item1,item2,item3,item4 are added once again.

I've try to add the check if (savedInstanceState == null) before the transaction of the MenuFragment but doesn't change anything.

What should I do to make MenuFragment be popped up from the back Stack without being inflated again with these items ?

Thanks.

Answer 1

Take a look at the Fragment lifecycle. onActivityCreated() will be called everytime when returning to aFragment. Try, instead, to move your implementation to onCreate() and that should fix your duplication issue.

Answer 2

Probably you can also check for the size of the arraylist and then clear it onActivityCreated() before populating the arrayList.

     if(m_parts != null && m_parts.size()>0){

        //Clear the contents of the arrayList m_parts

          m_parts.clear();
       }

And then add the data to the arrayList.