NullOutAdapter.diff

class MainActivityFragment : Fragment() {
  // Discard permanent reference to the adapter
  val adapter = MainRecyclerViewAdapter()
 
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    return inflater.inflate(R.layout.fragment_activity_main, container, false)
  }
 
+ override fun onDestroyView() {
+   super.onDestroyView()
+   // Note that this recyclerView is an old one
+   // and different instance from the one in onViewCreated.
+   recyclerView.adapter = null
+ }
+
  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState) 
    // Note that this recyclerView is a new one
    // and different instance from the one in onDestroyView.
    recyclerView.adapter = adapter 
  }
}