Swift 4 Codable decoding json

Question

I am trying to implement a new protocol Codable, so I added Codableto my structure, but I am stuck in JSON decoding .

Here is what I had before:

Struct -

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

Customer -

...

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")
}

Here is what I have, except that I cannot determine the part of the decoder:

Struct -

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

Customer -

...

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

He prints "Doesn't work," because I can't get past the part decoder.decode. Any ideas? Print any additional code as needed, thanks!

EDIT:

JSON API Example:

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

If I print self.jsonResponse, I get the following:

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";
}

My new code is:

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")
}

Answer 1

If your JSON has a structure

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

themes.

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

JSON:

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

, Question, .

Answer 2

, JSON, , :

{
  "themes": [
    { "title": ..., "question": ..., "answer": ... },
    { "title": ..., "question": ..., "answer": ... },
    { ... }
  ],
  ...
}

, , [Question] . , themes, [Question]. , [Question] themes.