【发布时间】：2016-03-06 02:13:11
【问题描述】：
我正在尝试从 Firebase 中提取排行榜数据。当我查看“快照”数据时，我能够以正确的顺序获取数据。一旦我到达 var json = JSON(snapshot.value) 的行，数据就会失去其顺序。
我正在尝试将数据解析为 swift 对象，以便它们可以在我的 swift 应用程序中作为有序排行榜使用/显示。我可以很容易地找到我的数据出现故障的解决方法，但这让我很困扰。
func getScoresData() {
let scoresRef = ref.childByAppendingPath("/High Scores")
scoresRef.queryLimitedToFirst(10).observeSingleEventOfType(.Value, withBlock: { snapshot in
print(snapshot)
var json = JSON(snapshot.value)
print(json)
let theKeys = json.dictionary!.keys
for key in theKeys {
self.timeStampArray.append(key)
let tempName = json[key]["Name"]
self.namesArray.append(String(tempName))
let tempScore = json[key]["Score"]
self.scoresArray.append(String(tempScore))
}
})
}
这是我从打印（快照）中正确排序的输出：
Snap (High Scores) {
"-KC3MktE1jS5z9-tTEgJ" = {
".priority" = "-9";
Date = "1457140993.669797";
Name = brendan;
Score = 9;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktM-rWmoitem8na" = {
".priority" = "-9";
Date = "1457140993.677347";
Name = brendan;
Score = 9;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktW0iJfkAKjlCy4" = {
".priority" = "-9";
Date = "1457140993.686348";
Name = brendan;
Score = 9;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktapH6Mebw2sAUe" = {
".priority" = "-10";
Date = "1457140993.692581";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktbOyltGaJZ_XtD" = {
".priority" = "-10";
Date = "1457140993.694163";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktjFj6VVAJfitZp" = {
".priority" = "-10";
Date = "1457140993.701368";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3Mktk0_f6_eM8wP1x" = {
".priority" = "-10";
Date = "1457140993.702492";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3MktrZaStt9b5pID_" = {
".priority" = "-10";
Date = "1457140993.709843";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3QALPl38gbDy4xLE2" = {
".priority" = "-10";
Date = "1457141888.477473";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
"-KC3qGAqZiJ9Vs40MwG7" = {
".priority" = "-10";
Date = "1457148990.24583";
Name = brendan;
Score = 10;
UUID = "BD561F1C-72A8-4A01-A71A-850682E49D61";
};
}
这是我在 print(json) 行中排序不正确的数据：
{
"-KC3MktrZaStt9b5pID_" : {
"Score" : "10",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.709843,
"Name" : "brendan"
},
"-KC3QALPl38gbDy4xLE2" : {
"Score" : 10,
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457141888.477473,
"Name" : "brendan"
},
"-KC3MktW0iJfkAKjlCy4" : {
"Score" : "9",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.686348,
"Name" : "brendan"
},
"-KC3MktbOyltGaJZ_XtD" : {
"Score" : "10",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.694163,
"Name" : "brendan"
},
"-KC3Mktk0_f6_eM8wP1x" : {
"Score" : "10",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.702492,
"Name" : "brendan"
},
"-KC3MktM-rWmoitem8na" : {
"Score" : "9",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.677347,
"Name" : "brendan"
},
"-KC3MktapH6Mebw2sAUe" : {
"Score" : "10",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.692581,
"Name" : "brendan"
},
"-KC3qGAqZiJ9Vs40MwG7" : {
"Score" : 10,
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457148990.24583,
"Name" : "brendan"
},
"-KC3MktjFj6VVAJfitZp" : {
"Score" : "10",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.701368,
"Name" : "brendan"
},
"-KC3MktE1jS5z9-tTEgJ" : {
"Score" : "9",
"UUID" : "BD561F1C-72A8-4A01-A71A-850682E49D61",
"Date" : 1457140993.669797,
"Name" : "brendan"
}
}
由于我使用 json 对象来获取键，从而填充数组，因此数组中的数据是乱序的。
我错过了什么？
【问题讨论】：
-
JSON 字典键未排序。会不会是这个问题？
-
这里有几件事。 Firebase 的顺序概念由您定义；您需要一个密钥来让 Firebase 在读入数据时知道如何对其进行排序。如果您想要一个按时间顺序排列的顺序，那么 .orderBy 时间戳。如果你想按分数排序，那么 .orderBy 分数。不要假设您的 Firebase 数据会被排序 - 它们可能是按键排序的，但这可能不是您想要的。要正确回答问题，请定义您希望数据排序的方式，我们将向您展示如何实现。
标签： json swift firebase swifty-json