Loader does not refresh adapter after finishing in fragment

Question

---

EDIT: It looks like ViewPager does not reflect change of underlying adapter - swapCursor() is called correctly, but getItem() is never called. I found a solution to similar problem on SO, but it does not helped in my case. EDIT 2 & SOLUTION: Thanks to this answer I found out that I'm providing a FragmentManager instead of ChildrenFragmentManager to CalendarPageAdapter.

---

I had SherlockFragmentActivity, which held a ViewPager. The same activity implemented LoaderCallbacks, which refreshed myAdapter in the onLoadFinished().

I moved this activity to a Fragment - so it extends SherlockFragment and still implements LoaderCallbacks, but swapping cursor stopped working. In onLoadFinished() correct data provided in cursor, but nothing is swapped. I didn't changed anything in my adapter nor fragment for pager filling. Where can be problem?

My new fragment is as follows:

public class MyFragment extends SherlockFragment implements LoaderCallbacks<Cursor> {
    private CalendarPageAdapter myAdapter;
    private ViewPager viewPager;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.my_fragment, container, false);

        myAdapter = new CalendarPageAdapter(getChildFragmentManager());  // <- EDIT 2
        viewPager = (ViewPager) view.findViewById(R.id.pager);
        viewPager.setAdapter(myAdapter);

        return view;
    }

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

        getLoaderManager().initLoader(0, null, this);
    }

    . . . .

    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        myAdapter.swapCursor(data);
            viewPager.setCurrentItem(data.getCount());  // skip to last column
        printoutCursorContent();  // prints out correct cursor content
    }
}

And my adapter is simple just like this:

public class CalendarPageAdapter extends FragmentStatePagerAdapter {
    private Cursor cursor;

    public CalendarPageAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        cursor.moveToPosition(position);
        int calendarId = cursor.getInt(cursor.getColumnIndex(CalendarTable.COLUMN_ID));

        return DayFragment.newInstance(calendarId);
    }

    @Override
    public int getCount() {
        if (cursor == null)
            return 0;
        else
            return cursor.getCount();
    }

    public void swapCursor(Cursor c) {
        if (cursor == c)
            return;

        cursor = c;
        notifyDataSetChanged();
    }

    public Cursor getCursor() {
        return cursor;
    }
}

Answer 1

If I understood correctly, your Cursor loads the propper data but the AdapterView doesn't reflect that change. If that's the case try adding this line at the end of your onLoadFinished(Loader<Cursor> loader, Cursor data) method:

myAdapter.notifyDataSetChanged();

Answer 2

Oh my! The second edit was right: use getChildFragmentManager() instead of getFragmentManager(). My change just does not apply, until I uninstalled application and/or cleared the project. Damn you, Eclipse!

Answer 3

@shmoula @NitroNbg

I have the same problem as both of you, but in a different situation

I have an activity with a viewpager (calendar too) and every page is a fragment with a loader:

Activity

...
fragmentPagerAdapter = new MainFragmentPagerAdapter(getSupportFragmentManager(), calendarView.getCalendarDays());
...

FragmentStatePagerAdapter

public class MainFragmentPagerAdapter extends FragmentStatePagerAdapter {

...

public MainFragmentPagerAdapter(FragmentManager fm, ArrayList<CalendarDay> calendarDays) {
    super(fm);

    ...
}

public int getCurrentIndex(String currentDate) {
    int index = dateTimes.indexOf(currentDate);
    return index;
}

@Override
public Fragment getItem(int i) {
    return EventByDayFragment.newInstance(dateTimes.get(i));
}

@Override
public int getCount() {
    return dateTimes.size();
}

}

Fragment

public class EventByDayFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    containerView = inflater.inflate(R.layout.fragment_event_by_day, container, false);
    findViews();
    return containerView;
}

...

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    mainEventsAdapter.swapCursor(data);
    listView.onRefreshComplete();
    mainEventsAdapter.notifyDataSetChanged();
}

...



 private void setInitData() {
     mainEventsAdapter = new MainEventsAdapter(getActivity());
     listView.setAdapter(mainEventsAdapter);
 }

 ...

}

But In my case I can't use getChildFragmentManager()