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.getC         


        

Answer 1

I had a similar problem, in my case getFragmentManager().getBackStackEntryCount() was always returning zero.

My problem was I've using support fragments:

Fragment fragment = new MyFragment();
// note getSupportFragmentManager() instead getFragmentManager()
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame, fragment)
.addToBackStack(null)
.commit();

fragmentManager.executePendingTransactions();

and I've checking getFragmentManager() backStackEntryCount, which always returns zero (it's using another fragment manager):

@Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() > 0 ) {
        getFragmentManager().popBackStack();            
    }
}

instead of getSupportFragmentManager, which returns the correct number:

@Override
public void onBackPressed() {
    if (getSupportFragmentManager().getBackStackEntryCount() > 0 ) {
        getSupportFragmentManager().popBackStack();         
    }
}

Hope it helps!