Swift 4 Codable解码json

SRMR

我正在尝试实现新Codable协议,因此我将其添加Codable到了struct中,但仍无法解码JSON

这是我以前的经历:

结构-

struct Question {
    var title: String
    var answer: Int
    var question: Int
}

客户-

...

guard let data = data else {
    return
}

do {
    self.jsonResponse = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String: Any]
    let questionItems = self.jsonResponse?["themes"] as! [[String: Any]]

    questionItems.forEach {
        let item = Question(title: $0["title"] as! String,
                            answer: $0["answer"] as! Int,
                            question: $0["question"] as! Int)
        questionData.append(item)
    }

} catch {
    print("error")
}

这是我现在所拥有的,除了我不知道解码器部分:

结构-

struct Question: Codable {
    var title: String
    var answer: Int
    var question: Int
}

客户-

...

let decoder = JSONDecoder()
if let questions = try? decoder.decode([Question].self, from: data) {
    // Can't get past this part
} else {
    print("Not working")
}

它打印“不起作用”,因为我无法通过decoder.decode零件。有任何想法吗?将根据需要发布任何其他代码,谢谢!

编辑:

API JSON示例:

{
  "themes": [
    {
      "answer": 1,
      "question": 44438222,
      "title": "How many letters are in the alphabet?"
    },
    {
      "answer": 0,
      "question": 44438489,
      "title": "This is a random question"
    }
  ]
 }

如果我打印,self.jsonResponse我会得到:

Optional(["themes": <__NSArrayI 0x6180002478f0>(
{
    "answer" = 7;
    "question" = 7674790;
    title = "This is the title of the question";
},
{
    "answer_" = 2;
    "question" = 23915741;
    title = "This is the title of the question";
}

我的新代码:

struct Theme: Codable {
    var themes : [Question]
}

struct Question: Codable {
    var title: String
    var answer: Int
    var question: Int
}

...

if let decoded = try? JSONDecoder().decode(Theme.self, from: data) {
    print("decoded:", decoded)
} else {
    print("Not working")
}
瓦迪安

如果您的JSON具有结构

{"themes" : [{"title": "Foo", "answer": 1, "question": 2},
             {"title": "Bar", "answer": 3, "question": 4}]}

您需要该themes对象的等效项添加此结构

struct Theme : Codable {
    var themes : [Question]
}

现在您可以解码JSON了:

if let decoded = try? JSONDecoder().decode(Theme.self, from: data) {
    print("decoded:", decoded)
} else {
    print("Not working")
}

包含的Question对象被隐式解码。

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