@Override
 public void onDestroyView() {
   numColumnsSubscription.unsubscribe();
   searchSubscription.unsubscribe();
   super.onDestroyView();
 }
 @Override
 public void onPause() {
   unregisterForEvents();
   super.onPause();
 }
 @Override
 public void onSaveInstanceState(Bundle outState) {
   adapter.onSaveInstanceState(outState);
   super.onSaveInstanceState(outState);
 }
 @Override
 public void onResume() {
   super.onResume();
   registerForEvents();
 }