listview中的checkbox onclick()错误

public class MyAdapter extends BaseAdapter {
    private List<Item> itemList;
    private Context context;

    public MyAdapter(List<Item> itemList, Context context) {
        this.itemList = itemList;
        this.context = context;
    }

    @Override
    public int getCount() {
        return itemList.size();
    }

    @Override
    public Object getItem(int position) {
        return itemList.get(position);
    }

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

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

        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.checkbox = convertView.findViewById(R.id.checkbox);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        final Item item = itemList.get(position);
        viewHolder.checkbox.setChecked(item.isSelected());

        viewHolder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                item.setSelected(isChecked);
                // 在这里进行相关的数据更新操作
            }
        });

        return convertView;
    }

    private static class ViewHolder {
        CheckBox checkbox;
    }
}