android - Removing a Fragment from the back stack

Question

I have a 3 fragments in an activity when the a tablet is held in portrait. However I only have 2 of these fragments when in landscape. The problem I am having is when going from portrait to landscape the activity is creating the 3rd fragment. I receive and error as this fragment cannot be created.

I have worked out that this fragment is being created because it is in the back stack.

I have tried to remove the fragment in the onDestroy method by using

FragmentTransaction f = fragmentManager.beginTransaction();
f.remove(mf);
f.commit();

However the I get an error saying that I cannot use this function after the onSaveInstanceState

What would be the correct way of taking this fragment out of the back stack?

Update

I should probably add that the fragment I am having problems with is a mapFragment from this libary

https://github.com/petedoyle/android-support-v4-googlemaps

The way I use it is like so

mf = MapFragment.newInstance(1, true);

ft = fragmentManager.beginTransaction();
ft.replace(R.id.mapContainer, mf);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.addToBackStack("map");
ft.commit();

Answer 1

You add to the back state from the FragmentTransaction and remove from the backstack using FragmentManager pop methods:

FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove(myFrag);
trans.commit();
manager.popBackStack();