添加到当前值的SQLite [英] Adding on to the current value SQLite

问题描述

我有谁拥有设定在'5'的学分初始值的用户。现在，我想创建，这将允许用户添加到这个数字的方法，例如， 2，这将随后在数据库列更新该行成为7.

不过，我不能让我的当前的方法来做到这一点。

当前方法：

 公共无效UpdateUser两个（串钱）
    {
        字符串selectQuery =SELECT+ KEY_CREDITS +由+
                                 DATABASE_TABLE +，其中+ KEY_ROWID +=+ 0;
        SQLiteDatabase分贝= this.getWritableDatabase（）;
        光标C = db.rawQuery（selectQuery，NULL）;
        INT oldMoney = 0;
        如果（c.moveToFirst（））
        {
            oldMoney =的Integer.parseInt（c.getString（4））;
        }
        ContentValues​​ cvUpdate =新ContentValues​​（）;
        cvUpdate.put（KEY_CREDITS，（oldMoney +钱））;
        字符串过滤器= KEY_ROWID +=+ 0;
        db.update（DATABASE_TABLE，cvUpdate，过滤器，NULL）;
    }
 

我随后致电上述方法在另一个活动：

 公共无效的onClick（查看arg0中）
{
    开关（arg0.getId（））{
    案例R.id.topup：        布尔的工作= TRUE;
        尝试{
        串钱= spinner.getSelectedItem（）的toString（）。        UDbHelper UD =新UDbHelper（本）;
        ud.open（）;
        ud.upDateUser（钱）;
        ud.close（）;
 

解决方案

更改以下步骤才能oldmoney的值

oldMoney = c.getInt（c.getColumnIndex（KEY_CREDITS））;

你也不能添加字符串来得到一个整的总价值。找到前总这样的价值的钱转换为整数

INT钱=的Integer.parseInt（钱）;

如果您有KEY_CREDITS列字符串数据类型，然后找到后总你应该把它转换回字符串更新前

cvUpdate.put（KEY_CREDITS，将String.valueOf（oldMoney +钱））;

I have a user who has a starting value for their credits set at '5'. Now I want to create a method which will allow the user to add on to that number, e.g. 2. This will then update the row in the database column to become 7.

However I cant get my current method to do this.

Current method:

    public void upDateUser(String money) 
    {
        String selectQuery = "SELECT " + KEY_CREDITS + " from " + 
                                 DATABASE_TABLE + " where " + KEY_ROWID + " = " + 0;
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor c = db.rawQuery(selectQuery, null);
        int oldMoney = 0;
        if (c.moveToFirst()) 
        {         
            oldMoney = Integer.parseInt(c.getString(4));
        }
        ContentValues cvUpdate = new ContentValues();
        cvUpdate.put(KEY_CREDITS, (oldMoney + money));
        String filter = KEY_ROWID + "=" + 0;
        db.update(DATABASE_TABLE, cvUpdate, filter, null);
    }

I then call the above method in an another activity:

public void onClick(View arg0)
{
    switch (arg0.getId()){
    case R.id.topup:

        boolean work = true;
        try{
        String money = spinner.getSelectedItem().toString();

        UDbHelper ud = new UDbHelper(this);
        ud.open();
        ud.upDateUser(money);
        ud.close();

解决方案

Change the following step to get the value of oldmoney

oldMoney = c.getInt(c.getColumnIndex(KEY_CREDITS));

Also you cannot add strings to get an integer total value. So convert the value money to integer before finding the total

int money =Integer.parseInt(money);

If you have a string data type for KEY_CREDITS column then after finding the total you should convert it back to string before updating

cvUpdate.put(KEY_CREDITS, String.valueOf(oldMoney + money));

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