自定义列表视图适配器类遇到问题

Question

我尝试创建一个扩展 SimpleAdapter 的类并覆盖 getView() 方法以防止我的列表视图出现颜色变化问题（当第一项回收到底部时，颜色也会再次出现）。但是，我是这样写的：

公共类适配器扩展 SimpleAdapter {

    public Adapter(Context context, List<? extends Map<String, ?>> data,
            int resource, String[] from, int[] to) {
        super(context, data, resource, from, to);
        // TODO Auto-generated constructor stub
    }

    class ViewHolder {
        TextView txt_textview = null;
        TextView txt_distance = null;
        TextView txt_starimage = null;
        ImageView txt_imageview = null;
    }

    HashMap<Integer, View> lmap = new HashMap<Integer, View>();

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        View view = super.getView(position, convertView, parent);
        ViewHolder holder = null;


        if (lmap.get(position) == null) {
            view =LayoutInflater.from(getApplicationContext()).inflate(
                    R.layout.activity_bank_listview_item,null);
            holder = new ViewHolder();
            holder.txt_starimage = (TextView) view
                .findViewById(R.id.bank_listview_starimage);
            holder.txt_imageview = (ImageView) view
                .findViewById(R.id.bank_listview_imageview);
            holder.txt_distance = (TextView) view
                    .findViewById(R.id.bank_listview_distance);
            holder.txt_textview = (TextView) view
                    .findViewById(R.id.bank_listview_textview);

            lmap.put(position, view);
            view.setTag(holder);
        } else {
            view = lmap.get(position);
            holder = (ViewHolder) view.getTag();
        }

        return view;
    }


} 

但是listview只出现第一页listview项，后面的页面是空的（只包含空布局）。我怎么解决这个问题？谢谢！

Answer 1

问题出在这一行：

if (lmap.get(position) == null) {

您应该检查 convertView 是否为空。如果它为空，则需要为新视图充气。如果不是，您应该重复使用它。

例如

@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
   LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   ViewHolder holder;
   if (convertView == null){
       convertView = inflater.inflate(R.layout.row, parent, false);
       holder = new ViewHolder();
       init(convertView, holder); // findViewById stuff
       convertView.setTag(holder);
   } else {
       holder = (ViewHolder) convertView.getTag();
   }

   setView(position, holder, convertView); // fill in the textviews, set background color etc.
   return convertView;

}