MenuItemCompat.getActionView always returns null

Finally I found the solution.

1. Changing namespace of actionViewClass from android:actionViewClass to app:actionViewClass

2. Implementing android.support.v7.widget.SearchView.OnQueryTextListener interface for current activity.

3. Directly use setOnQueryTextListener instead of SearchViewCompat.setOnQueryTextListener

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
     MenuInflater inflater = getMenuInflater();
     inflater.inflate(R.menu.menu, menu);
   
     MenuItem searchItem = menu.findItem(R.id.action_search);
     SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
     if (searchView != null) {
        searchView.setOnQueryTextListener(this);
     }
   
     return super.onCreateOptionsMenu(menu);
   }