android - Why FragmentManager's getBackStackEntryCount() return zero?

Question

private static void changeFragment(Fragment f, boolean init) {
        FragmentTransaction ft = fm.beginTransaction();
        ft.replace(R.id.info_content, f,f.getClass().getName());
        if(!init){
            ft.addToBackStack(null);
        }
        ft.commit();
    }

when I want to get the stack cout by call fm.getBackStackEntryCount(), it returns zero?

Answer 1

You have to call a fm.executePendingTransactions() after ft.commit() or before fm.getBackStackEntryCount(). Because the commit() only schedules the transactions for a later pass.