Issue with onBackPressed() is not refresh fragment
When back pressed your Fragment onResume will be called so you can write refresh code in onResume
for better understanding refer below link
http://developer.android.com/guide/components/fragments.html
If you want to add to back stack then you should use fragmentTransaction.add() . replace will just replace the fragment.
Also the right place to handle pop from backstack is through the use of OnBackStackChangedListener like this
getFragmentManager().addOnBackStackChangedListener( new FragmentManager.OnBackStackChangedListener() { @Override public void onBackStackChanged() { // find your fragment and do updates } });A good reference Fragments onResume from back stack