Question

所以我有两个我目前正在尝试访问的变量。 waterAmt和bucketExp。我不确定为什么waterAmt变量工作正常但另一个不是。似乎bucketExp没有以它应该的方式存储，即使它存储与waterAmt相同。提前感谢您的帮助。

访问数据库的代码：

//pull data
data = new Database(SetupTimerPC1.this);
data.open();
bucketExpTotal = data.getBucketExp();
totalWater = data.getWaterAmt();
data.close();

//add new data to old
bucketExpTotal += bucketExp;
totalWater += waterAmt;

//push data
data.open();
data.bucketExpEntry(bucketExpTotal);
data.waterAmountEntry(totalWater);
data.close();

将waterAmt输入数据库的代码：

public long waterAmountEntry(int waterAmt)
{
    ContentValues cv = new ContentValues();
    cv.put(KEY_WATER, waterAmt);
    return ourDatabase.insert(DATABASE_TABLE, null, cv);
}//end waterAmountEntry function

将bucketExp输入数据库的代码：

public long bucketExpEntry(int bucketExp)
{
    ContentValues cv = new ContentValues();
    cv.put(KEY_BUCKETEXP, bucketExp);
    return ourDatabase.insert(DATABASE_TABLE, null, cv);
}//end bucketExpEntry function

从数据库中提取waterAmt的代码：

public int getWaterAmt() 
{
    int waterAmount = 0, iWaterAmount = 0;
    String[] columns = new String[] {KEY_ROWID, KEY_ROCK, KEY_METEORROCK, KEY_WATER,
            KEY_POPULATION, KEY_SHOVEL, KEY_BUCKET, KEY_PICKAXE, KEY_SHOVELEXP,
            KEY_BUCKETEXP, KEY_PICKAXEEXP};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);

    if (c != null && c.getCount() > 0)
    {   
        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
        {
            iWaterAmount = c.getColumnIndex(KEY_WATER);
            waterAmount = c.getInt(iWaterAmount);
        }//end for
        c.close();
        return waterAmount;
    }//end if
    return 0;
}//end getWaterAmt function

从数据库中提取bucketExp的代码：

public int getBucketExp() 
{
    int bucketExp = 0, iBucketExp = 0;
    String[] columns = new String[] {KEY_ROWID, KEY_ROCK, KEY_METEORROCK, KEY_WATER,
            KEY_POPULATION, KEY_SHOVEL, KEY_BUCKET, KEY_PICKAXE, KEY_SHOVELEXP,
            KEY_BUCKETEXP, KEY_PICKAXEEXP};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);

    if (c != null && c.getCount() > 0)
    {
        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
        {
            iBucketExp = c.getColumnIndex(KEY_BUCKETEXP);
            bucketExp = c.getInt(iBucketExp);
        }//end for
        c.close();
        return bucketExp;
    }//end if
    return 0;
}//end getBucketExp function

Answer 1

现在您的查询相当于：

"SELECT [columns] FROM [table];"

这将返回表中的所有行。接下来，您将迭代整个结果集，并在每次迭代中将值设置为返回等于结果行中的某个列。

for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) { 
    bucketExp = cursor.getInt(...);
}

基本上这意味着bucketExp将等于结果最后一行中此列的值。

我想要的认为是特定行/记录的值。您需要更改查询以返回您正在查找的行，并摆脱for循环。这是一个通过ID查找特定行并返回bucketExp：

的示例

public int getBucketExp(long id) {
    String[] columns = new String[] { KEY_BUCKETEXP };
    String where = KEY_ROWID + " = ?";
    String[] whereArgs = new String[] { Long.toString(id) };

    Cursor cursor = ourDatabase.query(DATABASE_TABLE, columns, where, whereArgs,
            null, null, null);

    int bucketExp = 0;
    if (cursor.moveToFirst()) {
        bucketExp = cursor.getInt(cursor.getColumnIndex(KEY_BUCKETEXP));
    }

    return bucketExp;
}

数据库正确访问一个变量，而不是另一个变量

1 个答案: