Question

我有一个扩展Activity的A类。从A类开始，我调用了适配器类B，它扩展了BaseAdapter。

我正在覆盖方法中显示ListView数据 public View getView（final int position，View convertView，ViewGroup parent）

我从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，则数据未显示，表示数据库没有问题，只有更新显示才是问题。

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同样的帮助，请提供帮助。

Answer 1

在活动类中声明你的onClickListener，因为你正在为每个构建的视图创建一个新的监听器，然后在onClickListener onClick方法中执行此操作：

    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);
                    }
                }
            }

无法更新ListView数据

1 个答案: