FragmentPagerAdapter is not removing items (Fragments) correctly

Question

I have implemented the FragmentPagerAdapter and and using a List to hold all fragments for my ViewPager to display. On

Answer 1

The real problem is that FragmentPagerAdapter uses the position of the fragment in your list as ID. So if you add a new List or simply remove items "instantiateItem" item will find different fragments for new items in list...

@Override
public Object instantiateItem(ViewGroup container, int position) {
    if (mCurTransaction == null) {
        mCurTransaction = mFragmentManager.beginTransaction();
    }

    final long itemId = getItemId(position);

    // Do we already have this fragment?
    String name = makeFragmentName(container.getId(), itemId);
    Fragment fragment = mFragmentManager.findFragmentByTag(name);
    if (fragment != null) {
        if (DEBUG) Log.v(TAG, "Attaching item #" + itemId + ": f=" + fragment);
        mCurTransaction.attach(fragment);
    } else {
        fragment = getItem(position);
        if (DEBUG) Log.v(TAG, "Adding item #" + itemId + ": f=" + fragment);
        mCurTransaction.add(container.getId(), fragment,
                makeFragmentName(container.getId(), itemId));
    }
    if (fragment != mCurrentPrimaryItem) {
        fragment.setMenuVisibility(false);
        fragment.setUserVisibleHint(false);
    }

    return fragment;
}

and

  private static String makeFragmentName(int viewId, long id) {
    return "android:switcher:" + viewId + ":" + id;
}

and

     * Return a unique identifier for the item at the given position.
 * 

 * 
The default implementation returns the given position.
 * Subclasses should override this method if the positions of items can change.
 *
 * @param position Position within this adapter
 * @return Unique identifier for the item at position
 */
public long getItemId(int position) {
    return position;
}