getBackStackEntryCount() always returns 0 even after adding addToBackStack and executePendingTransactions()

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):

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

instead of getSupportFragmentManager, which returns the correct number:

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

Try this:

MapFragment mMapFragment = MapFragment.newInstance();    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();    mMapFragment.getMapAsync(this);    fragmentTransaction.add(R.id.container, mMapFragment);    fragmentTransaction.addToBackStack(null);    fragmentTransaction.commit();    getFragmentManager().executePendingTransactions();

I have changed this line:

fragmentTransaction.replace(R.id.container, mMapFragment);

to this:

fragmentTransaction.add(R.id.container, mMapFragment);

Pretty sure if you replace a fragment then its not in the backstack :)

I has similar problem. Thanks to this answer i create below code in my activity, instead of fragment, and this solution work fine:

getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {        @Override        public void onBackStackChanged() {            Log.d("ovech", "back stack changed");            Log.d("ovech", "back stack count = " + getSupportFragmentManager().getBackStackEntryCount());            if(getSupportFragmentManager().getBackStackEntryCount()>0) {                toolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp);            } else {                toolbar.setNavigationIcon(null);                Log.d("ovech", "hello without icon");            }            toolbar.invalidate();        }    });