ListView 的 Adapter 适配器模板

Adapter优化.png

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ListView中的Adapter优化的通用模板。

如果发现对ListView优化工作做完后，还会卡顿，可以检查notifyDataSetChanged()方法是否运用合理，频繁的调用此方法也会引发卡顿。

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1.构造函数的通用化

构造函数中的List不指定数据类型

public TemplateAdapter(Context context, List data) {
    this.mContext = context;
    this.mData = data;
}

2.创建 ViewHolder

// 使用ViewHolder
...
private static class ViewHolder {
    private TextView tvTitle, tvContent;
    private ImageView ivIcon;
}
...

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3.非空判断

@Override
public int getCount() {
    return null == mArrayList ? 0 : mArrayList.size();
}

4.getView中操作

getView中inflate的两种方式：

// 方式一 推荐使用方式一，简介
convertView = View.inflate(mContext, R.layout.item_ad, null);
// 方式二
convertView = mInflater.inflate(R.layout.item_layout, parent, false);

Override
public View getView(int position, View convertView, ViewGroup parent) {
    final ViewHolder viewHolder;
    //判断是否有缓存
    if (convertView == null || convertView.getTag == null) {
        //通过LayoutInflate实例化布局
        viewHolder = new ViewHolder();
        //convertView = mInflater.inflate(R.layout.item_layout, parent, false);
        convertView = View.inflate(mContext, R.layout.item_ad, null);
        viewHolder.ivIcon = (ImageView) convertView.findViewById(R.id.iv_icon);
        viewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tv_title);
        viewHolder.tvContent = (TextView) convertView.findViewById(R.id.tv_content);
        convertView.setTag(viewHolder);
      } else {
        //通过tag找到缓存的布局
        viewHolder = (ViewHolder) convertView.getTag();
      }

      // 数据渲染
      NewsBean newsBean = newsBeanList.get(position);
      
      // 所有的字段必须做非空判断
      String urlString = null == newsBean.newsIconUrl ? "" : newsBean.newsIconUrl;
      viewHolder.ivIcon.setTag(urlString); // 将ImageView与url绑定
      //普通异步加载
     // mImageLoader.showImageByThread(viewHolder.ivIcon,urlString);
      mImageLoader.showImageByAsyncTask(viewHolder.ivIcon,urlString);
      viewHolder.tvTitle.setText(newsBean.newsTitle);
      viewHolder.tvContent.setText(newsBean.newsContent);
      return convertView;
  }

5.完整的Adapter模板

public class TemplateAdapter extends BaseAdapter {

    private Context mContext;
    // 加上