无法更新 ListView 数据

Question

我有一个扩展 Activity 的 A 类。从 A 类，我正在调用扩展 BaseAdapter 的适配器 B 类。

我正在从被覆盖的方法中显示 ListView 数据 public View getView(final int position, View convertView, ViewGroup parent)

我正在从 SQLite 获取 ListView 的数据。现在单击特定列表项的取消按钮，我可以从数据库中删除记录数据，但无法刷新视图。仍在显示数据。但是如果我再次从主屏幕导航到屏幕，数据没有显示，说明数据库没有问题，只是更新显示有问题。

骨架代码如下：

class A extends Activity {

    B adapter ;
    ListView list ;

    public void onCreate(Bundle savedInstanceState) {

        list = (ListView) findViewById(R.id.textList);
        // I am calling the adapter

        adapter = new B(this, txtStr);
        list.setAdapter(adapter);
    }

    class B extends BaseAdapter{
        public View getView(final int position, View convertView, ViewGroup parent){

            // on click of the delete button , record is delated for a specific
            // listitem & the view needs to be updated , but I am unable to update the view

            holder.deleteImage.setOnClickListener(new OnClickListener() {
                    private int pos = position;
                    public void onClick(View v) {// (position)) -- what was this doing here? (dbreslau)

                        sampleDB.execSQL("DELETE FROM " + Constants.TABLE_NAME + " where id = 1");
                        adapter.notifyDataSetChanged();
                    }
                });
        }
    }
}

即使在调用 notifyDataSetChanged 之后，视图也没有得到更新。 如果有人已经实现了相同的功能，请提供帮助。

Answer 1

在你的适配器中声明你的 onClickListener，在活动类中，因为你正在为每个构造的视图创建新的监听器，然后在 onClickListener 的 onClick 方法中这样做：

    class A extends Activity {

                B adapter ;
                ListView list ;

                public void onCreate(Bundle savedInstanceState) {

                    list = (ListView) findViewById(R.id.textList);
                    // I am calling the adapter

                    adapter = new B(this, txtStr);
                    list.setAdapter(adapter);

                    list.setOnItemClickListener (listener);
                }


private OnItemClickListener listener = new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
         // TODO Auto-generated method stub
         sampleDB.execSQL("DELETE FROM " + Constants.TABLE_NAME + " where id = 1");
         //adapter.notifyDataSetChanged();
         ((B)adapter).notifyDataSetChanged();
    }
};

    **EDIT 1** 
    //with an onCLickListener...
    private OnClickListener deleteListener = new OnClickListener() {
            @Override
            public void onClick(View v) {
                int position = (int)v.getTag();
                            sampleDB.execSQL("DELETE FROM " + Constants.TABLE_NAME + " where id = 1");
                            ((B)adapter).notifyDataSetChanged());
            }
        };


                class B extends BaseAdapter{
                    public View getView(final int position, View convertView, ViewGroup parent){

                        // on click of the delete button , record is delated for a specific
                        // listitem & the view needs to be updated , but I am unable to update the view

    holder.deleteImage.setTag(position);                   
    holder.deleteImage.setOnClickListener(deleteListener);
    //...
    convertView.setTag(holder);
                    }
                }
            }