Question

我正在尝试使用Swift中的新（ish）可编码功能从JSON文件传递一些数据。我之前使用过以下语法没有问题。我相信我可能有一些设置错误，但是，我似乎无法理解为什么当JSON格式被JSON解析器批准时我会继续收到以下消息。

错误消息：

错误：dataCorrupted（swift.DecodingError.Context（codingPath：[]，debugDescription：＆＃34;给定数据无效JSON。＆＃34;，underlyingError：可选（错误域= NSCocoaErrorDomain代码= 3840＆＃ 34; JSON文本不以数组或对象和选项开头，以允许未设置片段。＆＃34; UserInfo = {NSDebugDescription = JSON文本不以数组或对象开头，并且选项允许未设置片段。}））< / p>

我的QuestionFactory文件中的代码......

class QuestionFactory {

func parseJSON(filename fileName: String) -> Quiz? {
    if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
        print(url)
        do {
            let data = try Data(contentsOf: url)
            let decoder = JSONDecoder()
            print("data received is \(data.count) bytes:\n\(data)")
            print(data)
            print(data as NSData)
            let jsonData = try decoder.decode(Quiz.self, from: data)

            print(jsonData)
        } catch {
            print("error:\(error)")
        }
    }
    return nil
}
}

我最初的ViewController中的代码：

class LaunchScreen: UIViewController {


  private var quiz: Quiz?
  private let jsonFileName = "QuizData"


 func viewDidLoad() {
    super.viewDidLoad()
    createQuiz()
 }


   private func createQuiz() {
    let questionFactory = QuestionFactory()
    guard let parsedQuiz = questionFactory.parseJSON(filename: jsonFileName) else {
        print("Error creating quiz")
        return
    }
    quiz = parsedQuiz
}

func movesToMainMenuScreen() {
    let transition = CATransition()
    transition.duration = 1.5
    transition.type = kCATransitionFade
    self.navigationController?.view.layer.add(transition, forKey:nil)
    let mainMenuVC: UIViewController = MainMenuViewController(quiz: quiz!) >> I am receiving an error here as well, perhaps due to my mainMenuVC's required init?
    navigationController?.pushViewController(mainMenuVC, animated: false)
}

在我的mainMenuViewController中：

class mainMenuViewController: UIViewController {

private var quiz: Quiz! {
    didSet {
    tableViewAdapter = AnswerTableViewAdapter(answers: quiz.questions[0].answers) >> Although, it is not obviously reaching this far to read through the JSON.
}

required init(quiz: Quiz) {
    super.init(nibName: nil, bundle: nil)
    defer {
        self.quiz = quiz
    }
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}
}

JSON看起来像这样......

{
"questions":[
             {
             "text": "1. Where will the 2022 World cup be held?",
             "answers": [
                         {
                         "text": "Qatar",
                         "isCorrect": true,
                         "answerType": "2"
                         },
                         {
                         "text": "دولة قطر",
                         "isCorrect": true,
                         "answerType": "1"
                         },
                         {
                         "text": "Jamaica",
                         "isCorrect": false,
                         "answerType": "0"
                         },
                         {
                         "image":"qatarFlag",
                         "isCorrect": true,
                         "answerType": "3"
                         }
                         ]
             }]
}

模型文件....

Quiz.swift

import Foundation

struct Quiz: Decodable {
  var questions: [Question]
}

Question.swift

import Foundation

struct Question: Decodable {
  var text: String
  var answers: [Answer]
}

Answer.swift

import Foundation

struct Answer: Decodable {
  var text: String
  var image: String
  var isCorrect: Bool
  var answerType: String
}

Answer 1

还有额外的

]
}

在最后两行添加删除这两个右括号并尝试解析JSON。

并将模型的属性设置为可选，以避免可以为空的崩溃。

模型文件....

Quiz.swift

import Foundation
struct Quiz: Decodable {
    var questions: [Question]?
}

Question.swift

import Foundation
struct Question: Decodable {
  var text: String?
  var answers: [Answer]?
}

Answer.swift

import Foundation
struct Answer: Decodable {
  var text: String?
  var image: String?
  var isCorrect: Bool?
  var answerType: String?
}

使用可编码解析JSON时出错

1 个答案: