Question

无法解决以下问题。我有SQLite数据库中保存的项目列表和项目名称。我使用onContextItemSelected方法来操作列表中的项目（添加和删除）。到目前为止，没有问题添加到数据库新名称并反映列表中的新项目;但删除让我发疯。当我单击删除时，项目将从列表中删除，但无法从数据库中删除名称。

这是代码

       if (item.getItemId() == CM_DELETE_ID) {

                AdapterView.AdapterContextMenuInfo acmi = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();

                // delete item from list
                bazar.remove(acmi.position);

                // get clicked item id from list                    
                rowID = acmi.id;

                // open database          
                datasource.openToWrite();

                if (cursor != null) {

Log.d(LOG_TAG, "--- Delete from mytable: ---");     

//delete from database
datasource.db.delete(DBHelper.TABLE, DBHelper.COLUMN_ID + " = " + rowID, null);

Log.d(LOG_TAG, "deleted row = " + datasource.db.delete(DBHelper.TABLE, DBHelper.COLUMN_ID + " = " + rowID, null));                                        

                } else {
                    Log.d(LOG_TAG, "Cursor is null");
                    cursor.close();
                }
                // close database
                datasource.close();

                myAdapter.notifyDataSetChanged();

                return true;

日志说

 05:12:08.403   1131    example.CustomAdapter   DEBUG       row inserted, ID = 1
05:12:08.413    1131    example.CustomAdapter   DEBUG       ID = 1, name = A1
05:12:22.853    1131    example.CustomAdapter   DEBUG       row inserted, ID = 2
05:12:22.864    1131    example.CustomAdapter   DEBUG       ID = 1, name = A1
05:12:22.864    1131    example.CustomAdapter   DEBUG       ID = 2, name = A2
05:12:23.623    111 jp.co.omronsoft.openwnn DEBUG   dalvikvm    GC_EXTERNAL_ALLOC freed 20K, 44% free 3471K/6151K, external 3902K/3936K, paused 169ms
05:12:41.833    1131    example.CustomAdapter   DEBUG       --- Delete from mytable: ---
05:12:41.984    1131    example.CustomAdapter   DEBUG       deleted row count = 0

在onCreate中我有dbReadAll方法，它列出了我拥有的所有项目和bazar.add（new Bazar（names，R.drawable.unread））;是我的ArrayList

    void dbReadAll() {

    bazar.add(new Bazar(names, R.drawable.unread));

    // подключаемся к базе данных для чтения данных
    datasource.openToRead();

    // получаем значение курсора        
    cursor = datasource.queryAll();

    if (cursor.moveToFirst()) {

        nameColIndex = cursor.getColumnIndex(DBHelper.COLUMN);

        do {

            Log.d(LOG_TAG, "ID = " + cursor.getInt(idColIndex) + ", name = " + cursor.getString(nameColIndex));

            names = cursor.getString(nameColIndex);

            bazar.add(new Bazar(names, R.drawable.unread));

        } while (cursor.moveToNext());

    } else {
        cursor.close();
        datasource.close();
    }
}

Answer 1

试试这个：

//delete from database
datasource.db.delete(DBHelper.TABLE, DBHelper.COLUMN_ID + "=?", new String[]{Long.toString(rowID)});

似乎删除语句使用预先准备的查询有关详细信息，请参阅this sof question

更新将rowId更改为Long.toString(rowId)我们需要在字符串数组中输入字符串

Answer 2

我认为你正在映射行id错误，rowid可能不等于acmi.id。

所以你可以做的是从游标

获取行ID

cursor.movetoPosition(acme.id);    
rowid = cursor.getLong(cursor.getColumnIndex(DBHelper.COLUMN_ID))

无法从数据库中删除

2 个答案: