Replace one Fragment with another in ViewPager

After so many hours spent, I’ve found correct solution modifying code in that answer.

It replaces Fragment in first page of ViewPager with another one, and if you return back from second Fragment, first Fragment is correctly displayed. Doesn’t matter Fragment displayed in first page, if you swipe from one page to another, it doesn’t change its Fragment.

Here is my code:

FragmentActivity

public class TabsFacturasActivity extends SherlockFragmentActivity {

    public void onBackPressed() {
        if(mPager.getCurrentItem() == 0) {
            if (mAdapter.getItem(0) instanceof DetallesFacturaFragment) {
                ((DetallesFacturaFragment) mAdapter.getItem(0)).backPressed();
            }
            else if (mAdapter.getItem(0) instanceof FacturasFragment) {
                finish();
            }
        }
    }

    private static class MyAdapter extends FragmentPagerAdapter {

        private final class FirstPageListener implements
        FirstPageFragmentListener {
            public void onSwitchToNextFragment() {
                mFragmentManager.beginTransaction().remove(mFragmentAtPos0)
                .commit();
                if (mFragmentAtPos0 instanceof FacturasFragment){
                    mFragmentAtPos0 = new DetallesFacturaFragment(listener);
                }else{ // Instance of NextFragment
                    mFragmentAtPos0 = new FacturasFragment(listener);
                }
                notifyDataSetChanged();
            }
        }

        private String[] titles = { "VER FACTURAS", "VER CONSUMO", "INTRODUCIR LECTURA" };
        private final FragmentManager mFragmentManager;
        public Fragment mFragmentAtPos0;
        private Context context;
        FirstPageListener listener = new FirstPageListener();

        public MyAdapter(FragmentManager fragmentManager) {
            super(fragmentManager);
            mFragmentManager = fragmentManager;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return titles[position];
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
            case 0: // Fragment # 0
                if (mFragmentAtPos0 == null)
                {
                    mFragmentAtPos0 = new FacturasFragment(listener);
                }
                return mFragmentAtPos0;

            case 1: // Fragment # 1
                return new ConsumoFragment();
            case 2:// Fragment # 2
                return new LecturaFragment();
            }
            return null;
        }

        @Override
        public int getCount() {
            return titles.length;
        }

        @Override
        public int getItemPosition(Object object)
        {
            if (object instanceof FacturasFragment && 
                    mFragmentAtPos0 instanceof DetallesFacturaFragment) {
                return POSITION_NONE;
            }
            if (object instanceof DetallesFacturaFragment && 
                    mFragmentAtPos0 instanceof FacturasFragment) {
                return POSITION_NONE;
            }
            return POSITION_UNCHANGED;
        }

    }

}

FirstPageFragmentListener

public interface FirstPageFragmentListener {
    void onSwitchToNextFragment();
}

FacturasFragment (FirstFragment)

public class FacturasFragment extends ListFragment implements FirstPageFragmentListener {

    static FirstPageFragmentListener firstPageListener;

    public FacturasFragment() {
    }

    public FacturasFragment(FirstPageFragmentListener listener) {
        firstPageListener = listener;
    }

    public void onListItemClick (ListView l, View v, int position, long id) {
        firstPageListener.onSwitchToNextFragment();
    }
}

DetallesFacturaFragment (SecondFragment)

public class DetallesFacturaFragment extends SherlockFragment {

    static FirstPageFragmentListener firstPageListener;

    public DetallesFacturaFragment() {
    }

    public DetallesFacturaFragment(FirstPageFragmentListener listener) {
        firstPageListener = listener;
    }

    public void backPressed() {
        firstPageListener.onSwitchToNextFragment();
    }
}