安卓 ListView : how to notify datasource when delete one row?

Question

我在每一行添加了一张删除图片，所以当点击图片删除这一行时，MyDapater的代码如下:

public View getView(int position, View convertView, ViewGroup parent) {
    View view = null;
    LayoutInflater inflater = ((Activity) context).getLayoutInflater();

    if (convertView == null) {
        view = inflater.inflate(R.layout.row, null);
        ItemViewHolder holder = new ItemViewHolder();
        ...
        holder.deleteImage = (ImageView) view.findViewById(R.id.delete_icon);

        holder.deleteImage.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {
                int pos = (Integer)v.getTag();
                _list.remove(pos); // _list is a List storage the data
                notifyDataSetChanged();
            }

        });

        view.setTag(holder);
    } else {
        view = convertView;
    }
    ItemViewHolder holder = (ItemViewHolder) view.getTag();
    holder.deleteImage.setTag(Integer.valueOf(position));

    return view;
}

在 Activity 中，我的数据存储了一个 List 和以下代码:

adapter = new MyAdapter(this, _list);//
listView.setAdapter(adapter);

所以，当点击 delete-image 时，这一行就会消失。我的问题是:activity 如何知道删除哪一行？

Answer 1

简而言之，它不是。

如果您想让 Activity 知道删除了哪一行，您需要告诉它。我的首选方法是接口(interface)。

public interface DeleteListener{
    public void rowDeleted(int pos);
}

并且 Activity 应该实现它

public class myActivity extends Activity implements DeleteListener{

创建适配器时传递 Activity 引用

adapter = new MyAdapter(this, _list, this);

并在适配器中触发删除事件

public MyAdapter(Context context, List _list, DeleteListener dListener){
    //save the listener to a field
}
...
        @Override
        public void onClick(View v) {
            int pos = (Integer)v.getTag();
            _list.remove(pos); // _list is a List storage the data
            dListener.rowDeleted(pos);
            notifyDataSetChanged();
        }