安卓里面如何实时刷新listview中item的局部地方？

Question

比如listview的item里面含有姓名、年龄和头像；我想让姓名和年龄实时刷新数据，头像不刷新，怎么用代码实现啊？

Answer 1

实现的方式参见下面的示例：

public class ParticalRefreshActivity extends ListActivity {

    String[] contents = new String[]{"aa","bb","cc","dd","ee","ff","gg","hh","ii","jj","kk","ll","mm","nn","oo","pp","qq","rr","ss","tt","uu","vv","ww","xx","yy","zz"};

    ParticalRefreshAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mAdapter = new ParticalRefreshAdapter(this,contents);
        setListAdapter(mAdapter);
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        mAdapter.refreshFixPosition(position);
    }

    class ParticalRefreshAdapter extends BaseAdapter{

        public String[] contents;
        LayoutInflater mInflater;

        public ParticalRefreshAdapter(Context context,String[] contents){
            this.contents = contents;
            mInflater = LayoutInflater.from(context);
        }
        @Override
        public int getCount() {
            return contents.length;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        //局部刷新的代码
        public void refreshFixPosition(int position){
            //刷新局部的item
            ViewHolder holder = map.get(position);
            String text = holder.textView.getText().toString().trim();
            holder.textView.setText(text+"-");
            //更改数据源，防止滑动时数据错误
            contents[position] = text+"-";
        }

        public Map<Integer,ViewHolder> map = new HashMap<>();

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            ViewHolder holder;
            if(convertView == null) {
                convertView = mInflater.inflate(R.layout.item_partical_refresh, null);
                holder = new ViewHolder();
                holder.textView = (TextView) convertView.findViewById(R.id.tv_partical_refresh);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.textView.setText(contents[position]);
            map.put(position, holder);
            return convertView;
        }

        class ViewHolder{
            TextView textView;
        }
    }
}

Answer 2

如果确实如你所说，item数目也没有变化，直接添加监听器，在里面更新就行了啊。

Answer 3

局部更新终究还是要伴随着listview的全局更新的，想想你局部更新，虽然可以内置什么监听器之类的对可视范围内的item进行控件的更新，但当你的item滑动滚出可视范围再滑回来，由于contentView的回收机制，你之前所做的更新将被重置到最初的状态，这时候往往你会考虑要弄一个记录的东西来记录之前修改的item的位置，还有一堆item上的控件的状态，还要对各种状态进行判断，复杂度不见得比全局更新代价小。而全局更新，你只需要根据item的位置修改和adapter绑定的数据集合中对应位置的数据实体，再调nodifyDataSetChanged来更新listview即可，虽然这样是全局更新，但不会引起listview的滚动，用户是感知不到是整体在刷新的。

Answer 4

更改数据源里的年龄姓名，然后notifyDataSetChanged