Android - addToBackStack() doesn't work?

Question

This is the function responsible for adding fragments to back stack:

public void populateContent(File f)
{

    ContentFragment cf = new ContentFragment(ctx, ac,         


        

Answer 1

I was adding, not replacing, but I had to call addToBackStack(null) before add(), not after, on the fragment which will close, not on the fragment which will stay open.

In class A (opened first)

FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.layout_a, f, Constants.FRAGMENT_KEY);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();

In class B (opened by class A)

FragmentTransaction ft = fm.beginTransaction();
ft.addToBackStack(null);
ft.add(R.id.layout_b, f, Constants.FRAGMENT_KEY);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();