ListView只更新某个item

方案1：

针对需要更新的item调用public View getView(int position, View convertView, ViewGroup parent)即可。

如：

public class AuthorListAdapter extends BaseAdapter {

    ...

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ...
        return convertView;
    }

    /**
     * 更新Item视图，减少不必要的重绘
     *
     * @param listView
     * @param position
     */
    public void updateItemView(ListView listView, int position) {
        //换算成 Item View 在 ViewGroup 中的 index
        int index = position - listView.getFirstVisiblePosition();
        if (index >= 0 && index < listView.getChildCount()) {
            //更新数据
            AuthorInfo authorInfo = mAuthorInfoList.get(position);
            authorInfo.setNickName("Google Android");
            authorInfo.setMotto("My name is Android .");
            authorInfo.setPortrait(R.mipmap.ic_launcher);
            //更新单个Item
            View itemView = listView.getChildAt(index);
            getView(position, itemView, listView);
        }
    }

}

　注意：在ListView中，getChildAt（int position)返回的item是指的可视区域内的第position个元素。使用getChildAt(index)的取值，只能是当前可见区域（列表可滚动）的子项！

　　　　即取值范围在 >= ListView.getFirstVisiblePosition() &&  <= ListView.getLastVisiblePosition();

 这里涉及到listview的复用原理，简单来说：一个元素很多的listview，如果页面的可视区域内最多可以看到6个元素，假如它们的index是0-5,那么在内存中只有6个item对象。当第7个item(即index=6)进入到可视区域的时候，那么其实是在复用index=0的item。由于在滑动时getView这个更新控件的方法执行非常频繁，所以肉眼是丝毫看不出这种复用的。

方案2

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    View view = super.getView(position, convertView, parent);
    view.setTag(getItemId(position));
    return view;
}

For the update check every element of list, if a view with given id is there it's visible so we perform the update.

private void update(long id)
{

    int c = list.getChildCount();
    for (int i = 0; i < c; i++)
    {
        View view = list.getChildAt(i);
        if ((Long)view.getTag() == id)
        {
            // update view
        }
    }
}

It's actually easier than other methods and better when you dealing with ids not positions! Also you must call update for items which get visible.