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我想从 SQLite 数据库中获取数据并通过 SimpleCursorTreeAdapter 填充我的 ExpandableListView，但它在某个地方失败了。我真的找不到什么问题，甚至不知道异常发生在哪里......

MyExpandableListAdapter：

private class MyExpandableListAdapter extends SimpleCursorTreeAdapter
    {       

        public MyExpandableListAdapter(Context context, Cursor cursor,
                int groupLayout, String[] groupFrom, int[] groupTo,
                int childLayout, String[] childFrom, int[] childTo) {
            super(context, cursor, groupLayout, groupFrom, groupTo, childLayout, childFrom,
                    childTo);
            // TODO Auto-generated constructor stub
        }

        @Override
        protected Cursor getChildrenCursor(Cursor groupCursor) {
            Log.d("Calling getChildrenCursor()","OK");
            Cursor childrenCursor = dbAdapter.getTrackedValuesByDate(groupCursor.getString(groupCursor.getColumnIndex(DbAdapter.KEY_VALUE_DATE)));
            Log.d("getChildrenCursor()", DatabaseUtils.dumpCursorToString(childrenCursor));
            startManagingCursor(childrenCursor);

            return childrenCursor;
        }       
    }

这是我的活动中设置 ListAdapter 的相关部分：

private void fillData()
    {
        Cursor dateCursor = dbAdapter.getAllDates();
        startManagingCursor(dateCursor);
        Log.d("fillData()", DatabaseUtils.dumpCursorToString(dateCursor));
        MyExpandableListAdapter myAdapter = new MyExpandableListAdapter(this, 
        dateCursor, 
        R.layout.expandablelist_header_date, 
        new String[] {DbAdapter.KEY_VALUE_DATE},    
        new int[]{R.id.expandablelist_header_date},             
        R.layout.listview_tracked_values, 
        new String[] {DbAdapter.KEY_INDICATOR_NAME, DbAdapter.KEY_INDICATOR_UNIT, DbAdapter.KEY_VALUE_VALUE},
        new int[]{R.id.list_trackedvalue_indicatorname, R.id.list_trackedvalue_unit, R.id.list_trackedvalue_value });

        Log.d("fillData()", "Creation successful");     
        this.expandableList.setAdapter(myAdapter);
        Log.d("fillData()", "Adapter set");
    }

以下是我的 dbAdapter 的两个使用功能：

public Cursor getTrackedValuesByDate(String dateString)
    {
        Cursor cursor = this.db.rawQuery("select * from "+DB_INDICATORS_TABLE+" i,"+ DB_VALUES_TABLE+" v where i."
        + KEY_INDICATOR_ROWID+"=v."+KEY_VALUE_INDICATOR_ID+" and v."+KEY_VALUE_DATE+"='"+dateString+"'", null);

        if(cursor!=null)
            cursor.moveToFirst();

        Log.d("getTrackedValuesByDate()", DatabaseUtils.dumpCursorToString(cursor));
        return cursor;
    }

    public Cursor getAllDates()
    {
        Cursor c = this.db.rawQuery("Select distinct "+KEY_VALUE_DATE+" from "+DB_VALUES_TABLE, null);
        if(c!=null)
            c.moveToFirst();

        Log.d("getAllDates()", DatabaseUtils.dumpCursorToString(c));
        return c;
    }

最后是 LogCat 的输出：

09-07 12:05:06.912: D/fillData()(1317): >>>>> Dumping cursor android.database.sqlite.SQLiteCursor@41219990
09-07 12:05:06.912: D/fillData()(1317): 0 {
09-07 12:05:06.912: D/fillData()(1317):    trackDate=07.09.2012
09-07 12:05:06.912: D/fillData()(1317): }
09-07 12:05:06.912: D/fillData()(1317): 1 {
09-07 12:05:06.912: D/fillData()(1317):    trackDate=08.08.2012
09-07 12:05:06.912: D/fillData()(1317): }
09-07 12:05:06.912: D/fillData()(1317): <<<<<
09-07 12:05:06.952: D/fillData()(1317): Creation successful
09-07 12:05:06.952: D/fillData()(1317): Adapter set
09-07 12:05:07.012: E/CursorWindow(1317): Failed to read row 0, column -1 from a CursorWindow which has 2 rows, 1 columns.
09-07 12:05:07.012: D/AndroidRuntime(1317): Shutting down VM
09-07 12:05:07.048: W/dalvikvm(1317): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-07 12:05:07.145: E/AndroidRuntime(1317): FATAL EXCEPTION: main
09-07 12:05:07.145: E/AndroidRuntime(1317): java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.database.CursorWindow.nativeGetLong(Native Method)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.database.CursorWindow.getLong(CursorWindow.java:507)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.database.AbstractWindowedCursor.getLong(AbstractWindowedCursor.java:75)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.CursorTreeAdapter$MyCursorHelper.getId(CursorTreeAdapter.java:436)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.CursorTreeAdapter.getGroupId(CursorTreeAdapter.java:191)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.ExpandableListConnector.getItemId(ExpandableListConnector.java:422)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.AbsListView.obtainView(AbsListView.java:2288)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.ListView.measureHeightOfChildren(ListView.java:1244)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.ListView.onMeasure(ListView.java:1156)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.view.View.measure(View.java:15172)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.RelativeLayout.measureChild(RelativeLayout.java:602)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:415)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.view.View.measure(View.java:15172)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
09-07 12:05:07.145: E/AndroidRuntime(1317):     at android.view.View.measure(View.java:15172)

如您所见，我的最后一个 debug.log 是 Adapter 设置为 ListView，但后来它是 finnito ...我什至没有收到覆盖函数 getChildrenCursor(Cursor groupCursor) 被调用过的日志消息，所以错误发生在我不知道在哪里......

救命啊，我要疯了……

4

3 回答 3

2

从 CursorTreeAdapter 的文档中，它是 SimpleCursorTreeAdapter 的间接父级，您可以看到：

游标必须包含名为“_id”的列，否则此类将不起作用。

您在查询中缺少的内容。

于 2013-06-20T10:14:25.493 回答
1

几点

您可能返回了一个空游标（即不返回 null），因此不要检查 c != null 而是尝试检查游标列数或检查 c.moveToNext 检查

还使用 try{}catch(SQLiteException) 包装所有 rawQuery 和 Cursor 方法

记录这个异常可能会揭示更多

于 2012-09-07T12:27:21.447 回答
0

好的，我无法让它与 SimpleTreeAdapter 一起工作......根本找不到错误。我现在所做的是跳过 TreeAdapter 并将游标的内容填充到 Collections 中，然后通过 BaseExpandableListAdapter 填充列表。

它更复杂，不如 SimpleTreeAdapter 优雅，但至少它现在可以工作；-)

于 2012-09-10T08:22:21.383 回答