Android 4.2: back stack behaviour with nested fragments

Question

With Android 4.2, the support library got support for nested fragments see here. I\'ve played around with it and found an interesting behaviour / bug regarding back stack an

Answer 1

The reason is that your Activity derives from FragmentActivity, which handles the BACK key press (see line 173 of FragmentActivity.

In our application, I'm using a ViewPager (with fragments) and each fragment can have nested fragments. The way I've handled this is by:

• defining an interface OnBackKeyPressedListener with a single method void onBackKeyPressed()
• implemented this interface in "top" fragments that ViewPager shows
• overriding onKeyDown and detecting BACK press, and calling onBackKeyPressed in a currently active fragment in the view pager.

Also note, that I'm using getChildFragmentManager() in the fragments to properly nest fragments. You can see a discussion and an explanation in this android-developers post.