baseadapter使用

public class NewsAdapter extends BaseAdapter
{
    private LayoutInflater mInflater;
    private List mNewsList;
    private Context context;//glide加载用
   
    public NewsAdapter(Context context, List listNewsBean){
        this.mInflater = LayoutInflater.from(context);
        this.mNewsList = listNewsBean;
        this.context=context;
    }

    @Override
    public int getCount ( )
    {   //适配器中数据集的数据个数
        return mNewsList==null?0:mNewsList.size();
    }

    @Override
    public Object getItem ( int position )
    {   //获取数据集中与所给索引对应的数据项
        return mNewsList.get(position);
    }

    @Override
    public long getItemId ( int position )
    {   //获取指定行对应的ID
        return position;
    }
  
    @Override
    public View getView (int position, View convertView, ViewGroup parent)
    {   //获取每一个Item显示内容view
        ViewHolder viewHolder=null; 
        //实例化view,获取控件id
        if (convertView == null) 
        { 
            //View未实例化，缓存池中无缓存；需要创建；
            //convertView的回收重用机制。
            convertView = mInflater.inflate(R.layout.newslistview_item, null); 
            viewHolder = new ViewHolder(); 
            viewHolder.title = (TextView) convertView.findViewById(R.id.item_title); 
            viewHolder.description = (TextView) convertView.findViewById(R.id.item_des); 
            viewHolder.thumb = (ImageView) convertView.findViewById(R.id.item_thumb);  
            //View中的setTag(Onbect)表示给View添加一个格外的数据，以后可以用getTag()将这个数据取出来。
            convertView.setTag(viewHolder); 
        } 
        else 
        { 
            viewHolder = (ViewHolder) convertView.getTag(); 
        } 
        //设置数据
        NewsBean newsBean =mNewsList.get(position); 
        viewHolder.title.setText(newsBean.getTitle()); 
        viewHolder.description.setText(newsBean.getDescription()); 
        Glide.with(context)
            .load(newsBean.getThumb())
            .into(viewHolder.thumb);
        return convertView;
        
    }
    //避免重复findViewById
    private class ViewHolder { 
        ImageView thumb; 
        TextView title; 
        TextView description;
    }
}

主活动代码