Android ListView 使用HashMap解决复用问题

public class MyAdapter extends BaseAdapter {   ......    private HashMap<Integer, View> hm = new HashMap<Integer, View>();   ......    @Override    public View getView(int position, View convertView, ViewGroup parent) {                ViewHolder holder = null;        if (hm.get(position) == null) {            convertView = View.inflate(context, R.layout.item, null);            holder = new ViewHolder();           ......            convertView.setTag(holder);            hm.put(position, convertView);        } else {            convertView = hm.get(position);            holder = (ViewHolder) convertView.getTag();        }       ......        return convertView;    }    class ViewHolder {        ......    }}