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从Android Sq lite检索数据后在Android上显示数据_Android_Sqlite_Android Sqlite - Fatal编程技术网

从Android Sq lite检索数据后在Android上显示数据

从Android Sq lite检索数据后在Android上显示数据,android,sqlite,android-sqlite,Android,Sqlite,Android Sqlite,我正在根据日期检索数据,但在运行我的应用程序时,它不会显示任何内容 这是我的密码: SQL查询: private Cursor getAllCurrentData() { String[] selectArg = new String[]{}; return db.query(Db_Contract.Db_Fieds.TABLE_NAME, null , Db_Contract.Db_Fie

我正在根据日期检索数据,但在运行我的应用程序时,它不会显示任何内容

这是我的密码:

SQL查询:

private Cursor getAllCurrentData()
    {
        String[] selectArg = new String[]{};

        return db.query(Db_Contract.Db_Fieds.TABLE_NAME,
                null ,
                Db_Contract.Db_Fieds.DATE+ "= 2018-11-10",
                selectArg,
                null,
                null,
                Db_Contract.Db_Fieds.TIMESTAMP);
    }
显示数据:

private  void totalMoney()
    {
        Cursor cursor = getAllCurrentData();
        double sum = 0.000d;
        double getMoney;
        while (cursor.moveToNext()) {
            getMoney = cursor.getDouble(cursor.getColumnIndex(Db_Contract.Db_Fieds.MONEY));

            sum += getMoney;
        }
        total.setText("Total money spent: " +sum);

    }

我是Android编程新手。我哪里做错了?。请纠正我,首先确保您已连接到数据库,并且由
db.query()
返回的
光标
不为空/null。然后像这样在游标上迭代

 private void totalMoney()
    {
        openDatabase();

        Cursor cursor =  getAllCurrentData();
        cursor.moveToFirst();
        double getMoney = 0;
        while (!cursor.isAfterLast()) {

           getMoney = cursor.getDouble(cursor.getColumnIndex(Db_Contract.Db_Fieds.MONEY));

            sum += getMoney;

            cursor.moveToNext();
        }

        total.setText("Total money spent: " + sum );

        closeDatabase();

    }

它显示什么?