android - 更新 BaseAdapter 的 setOnCheckedChangeListener 列表中的数据

Question

我有以下代码：

    public class MyListAdapter extends BaseAdapter {

    private final List<MyClass> mItems = new ArrayList<MyClass>();
...

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
    View rowView = convertView;
    final MyClass myItem = mItems.get(position);
    if (rowView == null) {
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        rowView = inflater.inflate(R.layout.my_item, null);
        ViewHolder viewHolder = new ViewHolder();
        viewHolder.cbView = (CheckBox) rowView.findViewById(R.id.cbCheckBox);
        viewHolder.cbView.setOnCheckedChangeListener(new OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                myItem.setState(isChecked);
            }
        });
        rowView.setTag(viewHolder);
    }

我对听众很不舒服。它指的是在 convertView 为 null 时创建的 myItem。如果我从列表中删除该项目（位置发生变化）怎么办？或者如果我在它前面添加一些项目？我的代码会因“空异常”而失败吗？还是执行不正确？我应该如何构建它？

Answer 1

如果 convertView 为空，则只需创建视图对象...现在，如果从列表中间删除视图，则从底部抬起视图并替换已删除视图的空间。并且当视图被抬起时，viewHolder 对象将创建新的并且视图保持更新的 viewHolder 对象。

@Override
    public View getView(int position, View convertView, ViewGroup parent) {
    View rowView = convertView;
    final MyClass myItem = mItems.get(position);
    if (rowView == null) {
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        rowView = inflater.inflate(R.layout.my_item, null);
       }
        ViewHolder viewHolder = new ViewHolder();
        viewHolder.cbView = (CheckBox) rowView.findViewById(R.id.cbCheckBox);
        viewHolder.cbView.setOnCheckedChangeListener(new OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                myItem.setState(isChecked);
            }
        });
        rowView.setTag(viewHolder);
    }