title: "androidx" Fragment[State]PagerAdapter fails on lollipop 5.0.1
body: <p>I have an activity with 3 tabs handled by androidx FragmentPagerAdapter.
  ViewPager contains a Fragment and Fragment contains some child Fragments.
  App works perfectly fine on android 7+ devices but it fails on lollipop 5.0.1.</p>
  
  <p>I tried using basic simple fragments to see if problem was fragment related but it was not.</p>
  
  <pre><code>public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
      try {
          if (getArguments() != null) {
              token = getArguments().getString("token");
              name = getArguments().getString("name");
              number = getArguments().getString("number");
          }
          View view = inflater.inflate(R.layout.frag_pending_layout, container, false);
          TextView txt_token = view.findViewById(R.id.txt_pending_token);
          TextView txt_name = view.findViewById(R.id.txt_pending_name);
          TextView txt_number = view.findViewById(R.id.txt_pending_number);
          RadioButton radio_cancel = view.findViewById(R.id.radio_cancel);
          RadioButton radio_confirm = view.findViewById(R.id.radio_confirm);
          Button btn_ok = view.findViewById(R.id.btn_pending_ok);
  
          txt_token.setText("Token: " + token);
          txt_name.setText("Name: " + name);
          txt_number.setText("Number: " + number);
  
          btn_ok.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View view) {
              //Toast.makeText(getActivity(), "test toast", Toast.LENGTH_SHORT).show();
              }
          });
  
          return view;
      } catch (Exception e){
          //StackTraceElement[] el = e.getStackTrace();
          //for(StackTraceElement elem : el){
          Toast.makeText(getActivity(), e.toString(), Toast.LENGTH_SHORT).show();//}
      return null;}
      }
  </code></pre>
  
  <p><strong><em>Error:</em></strong> Error inflating class &lt; Unknown > on lollipop 5.0.1</p>
  
  <p><strong><em>Update:</em></strong> issue seems to be with getChildFragmentManager.</p>