Android fragments over each other

Question

I've been working with fragments for a while now, but I regularly encounter a problem that just annoys me. Fragments remain drawn over each other some times. Now, I managed to isolate one use case for this, and it goes like this:

Add Fragment A (also use addToBackStack with a name "backstack_state")

Replace Fragment A with Fragment B (use addToBackStack)

Replace Fragment B with Fragment C WITHOUT using addToBackStack

at a given point use popBackStack("backstack_state", 0) and here comes the issue:

The backstack is popped until Fragment A but Fragment C is overlaid with Fragment A, both are visible at the same time. Is this normal behavior or is it me who makes a mistake?

Here's a remark also: all the fragments have transparent background.

Thanks!

Answer 1

This happens because the top fragment (in this case Fragment C) is not removed. You have to remove it first inside a fragment transaction. Try this:

FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
Fragment topFragment = fragmentManager.findFragmentById(R.id.fragment_container);
if (topFragment != null) {
    fragmentTransaction.remove(topFragment);
}    
fragmentTransaction.commit();
fragmentManager.popBackStack("backstack_state", 0);