在适配器中使用 getView 方法的优化方法 [重复]

Question

我明白了，每次调用 view.findViewById(R.id.title);是非常昂贵的操作。我如何通过存储这些 int 值来优化它。在 List Adapter 中使用的优化方式是什么？

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
        View view = convertView;
        final DataObject dataObject = getItem(position);
        if (view == null) {
        // No view created yet
        LayoutInflater layoutInflater = LayoutInflater.from(getContext());
        view = layoutInflater.inflate(layoutResourceId, parent, false);
        }
        if (view != null) {
        TextView title = (TextView) view.findViewById(R.id.title);
        TextView price = (TextView) view.findViewById(R.id.price);
        ImageView img = (ImageView) view.findViewById(R.id.profile_pic);
        RatingBar overallRating = (RatingBar)                                                 view.findViewById(R.id.overall_rating);

Answer 1

你应该像这样使用viewholder：

ViewHolder holder;

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    if (convertView == null) {
        holder = new ViewHolder();
        convertView = inflater.inflate(R.layout.chocolate_list_item,
                parent, false);
        holder.txtvwChocolateName = (TextView) convertView
                .findViewById(R.id.xtxtvwChocolateName);
        holder.imgvwChocolateIcon=(ImageView)convertView.findViewById(R.id.ximgvwChocolateIcon);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    holder.txtvwChocolateName.setText(alChocolate.get(position)
            .getStrChocolateName());
    holder.imgvwChocolateIcon.setImageResource(images[position]);
    return convertView;
}

class ViewHolder {
    TextView txtvwChocolateName;
    ImageView imgvwChocolateIcon;
}