为什么我在recycleview适配器上收到NullPointerException? [重复]

当我尝试使用ImageView的适配器setBaground时,会收到NullPoinerException。虽然我通过findViewById()方法在ViewHolder类中分配了它。我在哪里弄错了?

这是我得到一个NullPointerException

@Override
public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
    ItemData mItem = mData.get(position);
    holder.titleNews.setText(mItem.getTitle());
    holder.newsDescription.setText(mItem.getDescription());
    holder.newsImage.setBackground(LoadImageFromWebOperations(mItem.getUrlToImage())); // NullPointerExcpetion
}

但是我在这里分配

public class ViewHolder extends RecyclerView.ViewHolder {
        TextView titleNews;
        TextView newsDescription;
        ImageView newsImage;
        ViewHolder(View itemView) {
            super(itemView);
            titleNews = itemView.findViewById(R.id.newsDescription);
            newsDescription = itemView.findViewById(R.id.newsDescription);
            newsImage = itemView.findViewById(R.id.newsImage); // assign newsImage
        }
    }