Nested fragments: endless progress bar

I have a fragment in which the viewpager lies in which fragments A and B are loaded. I need to divide each of these fragments (A and B) into several fragments.

At the moment in the xml files of the fragments lies FrameLayout .

Fragment download code:

 FragmentTransaction transaction = getChildFragmentManager().beginTransaction(); transaction.add(R.id.frame1, new Fragment1)).add(R.id.frame2, new Fragment2).commit(); 

In the end, I get endless progress bar.