安卓SimpleCursorTreeAdapter挂起

Question

我正试着在我编写的一些代码中使用SimpleCursorTreeAdapter，以便于学习。发生的情况是，当我单击一个父对象时，它会展开并显示子对象，但之后我就不能再做任何事情了。我使用调试器遍历了代码，发现自己陷入了looper.loop中的一个永无止境的循环中。我已经在下面的代码片段中注释掉了所有实际工作的东西，但它仍然挂起。使用下面的代码片段，我预计单击第二个父对象会导致它展开(如箭头变化所示)。我在代码中留下了旧的东西(但注释掉了)，以显示我想要做的事情。

如果有任何建议或建议，我将非常感谢。

    private void showEvents(final Cursor cursor) {

    ExpandableListView lv1 = this.getExpandableListView();



    SimpleCursorTreeAdapter  adapter = new SimpleCursorTreeAdapter (this, cursor, R.layout.simplerow, FROM, TO, 
            R.layout.childrow, FROMCHILD, TOCHILD) {
        //@Override
        //public void setViewText(TextView v, String text) {
        //  super.setViewText(v, convText(v, text, cursor));
        //}

        @Override
        protected Cursor getChildrenCursor(Cursor parentCursor) {

            int groupPos = parentCursor.getPosition(); 
              Log.d("TEST", "getChildrenCursor() for groupPos " + groupPos); 

            String sql = "select f._id, f.NAME as ASSETCLASS, "
                    + "f.value as AMOUNT, "
                    + "0 as PERCENTAGE, "
                    + "0 as TARGET "
                    + "from funds f "
                    + "where f.asset_class = " + parentCursor.getInt(0) + ";";

            sql = "select f._id, f.NAME as FUNDNAME, "
                    + "f.value as AMOUNT_OWNED "
                    + "from funds f "
                    + "where 1  = 1;";



            Log.d("TEST", sql);

            //SQLiteDatabase db = pfdata.getReadableDatabase();

            //Cursor cursor = db.rawQuery(sql, null);
            //startManagingCursor(cursor);
            //return cursor;

            //Log.d("TEST", Integer.toString(cursor.getCount()));
            //return cursor;
            return null;
        }

    };

    // Log.d("TEST", Integer.toString(adapter.getCount()));

    lv1.setAdapter(adapter);

}

我尝试了这个建议，但我没有看到任何行为上的变化。这是我目前所拥有的：

    private void showEvents(final Cursor cursor) {

    ExpandableListView lv1 = this.getExpandableListView();


    MyExpandableListAdapter mAdapter = new MyExpandableListAdapter(cursor, this, 
            R.layout.simplerow, R.layout.childrow, 
               FROM, TO, 
               FROMCHILD, TOCHILD); 
        lv1.setAdapter(mAdapter); 
       }

public class MyExpandableListAdapter extends SimpleCursorTreeAdapter { 


public MyExpandableListAdapter(Cursor cursor, Context context, 
        int groupLayout, int childLayout, String[] groupFrom, 
        int[] groupTo, String[] childrenFrom, int[] childrenTo) { 
    super(context, cursor, groupLayout, groupFrom, groupTo, 
            childLayout, childrenFrom, childrenTo); 
} 

@Override 
protected Cursor getChildrenCursor(Cursor parentCursor) { 

    String sql = "select f._id, f.NAME as ASSETCLASS, "
            + "f.value as AMOUNT, "
            + "0 as PERCENTAGE, "
            + "0 as TARGET "
            + "from funds f "
            + "where f.asset_class = " + parentCursor.getInt(0) + ";";

    Log.d("TEST", sql);

    return null;        
} 

我试着实际运行查询并返回游标，但没有什么不同，所以我试着回到最基础的部分。如果任何人对正在发生的事情有任何想法，我将非常感谢。

Answer 1

我相信你的问题是因为你重写了SimpleCursorTreeAdapter而不是扩展它。当您这样做时，您需要重新创建它用来处理列表的所有方法(您还没有这样做)。

您有两个选择:添加所有缺少的方法，或者创建一个扩展SimpleCursorTreeAdapter的新类并将其用作适配器。最后一个(IMO)比第一个简单得多。您只需覆盖所需的方法。

下面是我的一个项目的示例。

mAdapter = new MyExpandableListAdapter(mGroupsCursor, getActivity(),
       R.layout.rowlayout_expgroup, R.layout.rowlayout_itemlist_exp,
       new String[] { "_id" }, new int[] { android.R.id.text1 },
       new String[] { GroceryDB.ITEM_NAME, GroceryDB.LISTITEM_QTY,
               GroceryDB.ITEM_UNIT }, new int[] { R.id.ListItem1,
               R.id.ListItem3, R.id.ListItem2 });
lv.setAdapter(mAdapter);

public class MyExpandableListAdapter extends SimpleCursorTreeAdapter {
    public MyExpandableListAdapter(Cursor cursor, Context context,
            int groupLayout, int childLayout, String[] groupFrom,
            int[] groupTo, String[] childrenFrom, int[] childrenTo) {
        super(context, cursor, groupLayout, groupFrom, groupTo,
                childLayout, childrenFrom, childrenTo);
    }

    @Override
    protected Cursor getChildrenCursor(Cursor groupCursor) {
        Cursor childCursor = mDbHelper.fetchChildren(GroceryListMain.group,
                groupCursor.getString(groupCursor.getColumnIndex("_id")),
                ListFragment_ShopList.listId);
        getActivity().startManagingCursor(childCursor);
        childCursor.moveToFirst();
        return childCursor;
    }

    protected void bindChildView(View view, Context context, Cursor cursor,
            boolean isLastChild) {
        TextView name = (TextView) view.findViewById(R.id.ListItem1);
        TextView qty = (TextView) view.findViewById(R.id.ListItem3);
        TextView unit = (TextView) view.findViewById(R.id.ListItem2);
        TextView cost = (TextView) view.findViewById(R.id.ListItem4);

        name.setText(cursor.getString(2));
        qty.setText(cursor.getString(1));
        unit.setText(cursor.getString(4));
        DecimalFormat df = new DecimalFormat("0.00");
        Double hold = Double.valueOf(cursor.getString(3));
        Double qtyhold = Double.valueOf(cursor.getString(1));
        Double total = hold * qtyhold;
        cost.setText("$" + df.format(total));
    }
}