How to implement NativeExpressAds with model class in recyclerview

How to set it on adapter with model class nativeExpressAdView incompatible error with model class. Please help me to solve the error.

private final List<Notification_model_item> mRecyclerViewItems; // list   

 @Override

public void onBindViewHolder(RecyclerView.ViewHolder holder, int position){
    int viewType = getItemViewType(position); 

adapter view

    switch (viewType) 
         {
        case MENU_ITEM_VIEW_TYPE:

            MenuItemViewHolder menuItemHolder = (MenuItemViewHolder) holder;
            Notification_model_item menuItem = (Notification_model_item)mRecyclerViewItems.get(position); 
            // Get the menu item image resource ID.
            // Add the menu item details to the menu item view.
            menuItemHolder.menuItemName.setText(menuItem.getUsername());
            break;
        case NATIVE_EXPRESS_AD_VIEW_TYPE:
            // fall through
        default:
            NativeExpressAdViewHolder nativeExpressHolder = 
(NativeExpressAdViewHolder) holder;
            NativeExpressAdView adView = (NativeExpressAdView) 
mRecyclerViewItems.get(position); //incompatible error with model class.

            ViewGroup adCardView = (ViewGroup) nativeExpressHolder.itemView;
            // The NativeExpressAdViewHolder recycled by the RecyclerView may be a different
            // instance than the one used previously for this position. Clear the
            // NativeExpressAdViewHolder of any subviews in case it has a different
            // AdView associated with it, and make sure the AdView for this position doesn't
            // already have a parent of a different recycled NativeExpressAdViewHolder.
            if (adCardView.getChildCount() > 0) {
                adCardView.removeAllViews();
            }
            if (adView.getParent() != null) {
                ((ViewGroup) adView.getParent()).removeView(adView);
            }

Add the Native Express ad to the native express ad view.

            adCardView.addView(adView);
    }
}