通过 segue 传递错误的数据

Question

我正在尝试随机化我的测验问题，如果答案不正确，则会出现转场。我认为这可能与我的 NewNumber() 有关，但我无法弄清楚。

有时它适用于前 3 个问题，但即使通过按钮选择了正确答案，也会触发 segue。

所以，我喜欢的是： - 随机问题（没有重复，但我不得不摆脱 list.remove 因为它更加混乱了正确答案） - 如果按下了错误的答案，我希望它触发具有正确相应信息的另一个屏幕

我列出了完整的代码，因为我不知道它是否也与我的订单或功能有关。

class RoundThree: UIViewController {

    @IBOutlet weak var FuelLevel: UIImageView!
    @IBOutlet weak var QuestionLabel: UILabel!
    @IBOutlet weak var Car: UIImageView!
    @IBOutlet weak var SmallTown: UIImageView!

    //Outlet for Buttons

    @IBOutlet weak var OptionA: UIButton!
    @IBOutlet weak var OptionB: UIButton!
    @IBOutlet weak var OptionC: UIButton!



    let allQuestions2 = QuestionBank2()
    var questionNumber: Int = 0
    var oldQNumber: Int = 0
    var score: Int = 0
    var selectedAnswer: Int = 0
    var fuelleackage: CGFloat = 0
    var wronganswer: Int = 0
    let screenSize: CGRect = UIScreen.main.bounds
    var questionsasked = [Int]()



    override func viewDidLoad() {
        newNumber()
        startQuiz()
        super.viewDidLoad()
        }

    @IBAction func answerPressed(_ sender: UIButton){
        if sender.tag == selectedAnswer {
            Car.frame.origin.x  += 40
            score += 1
            fuelleackage += 0.0
            NewYorkCity()

        }  else if sender.tag != selectedAnswer {
            fuelleackage += 40.0
            wronganswer += 1
            EducateYourself()
            NewYorkCity()


        }
        updateUI()

    }

    func updateQuestion(){
            QuestionLabel.text = allQuestions2.list[oldQNumber].question
            OptionA.setTitle(allQuestions2.list[oldQNumber].optionA, for: UIControl.State.normal)
            OptionB.setTitle(allQuestions2.list[oldQNumber].optionB, for: UIControl.State.normal)
            OptionC.setTitle(allQuestions2.list[oldQNumber].optionC, for: UIControl.State.normal)
            selectedAnswer = allQuestions2.list[oldQNumber].CorrectAns
        }




    func updateUI(){
        FuelLevel.frame.size.width = screenSize.width * (1.0-0.15 * CGFloat(wronganswer))
        oldQNumber = questionNumber
        newNumber()
        updateQuestion()
        questionsasked.append(questionNumber)
        }
        //Carol.frame.origin.x  += 30



    func startQuiz (){
        score = 0
        updateQuestion()
        updateUI()
    }


    func NewYorkCity(){
        if (Car.frame.origin.x + (Car.frame.width / 2))  > (SmallTown.frame.origin.x + SmallTown.frame.width) {
            performSegue(withIdentifier: "FinishWindow", sender: self)
        }
        else if (screenSize.width * (1.0-0.15 * CGFloat(wronganswer)) <= 0)
        { performSegue(withIdentifier: "saaaad", sender: self)
        }
    }

        override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
            if (segue.identifier == "PopUp2") {
                let vc1 = segue.destination as! CorrectInfoPopUp2
                vc1.InformationRoundNumber = oldQNumber
            }
        }
    func EducateYourself(){
        performSegue(withIdentifier: "PopUp2", sender: self)
    }

    func newNumber() {
        for _ in 0..<allQuestions2.list.count {
            var rand = Int(arc4random_uniform(UInt32(allQuestions2.list.count)))
            while questionsasked.contains(rand) {
                rand = Int(arc4random_uniform(UInt32(allQuestions2.list.count)))
            }
            questionNumber = rand
        }
    }


}

Answer 1

和Robert Dresler写的答案一样。

还有几个附加组件：

1. 最好对 segue 标识符使用常量而不是具体字符串：

例子：

struct SegueIdentifiers {      
    static let popUp = "PopUp"
    static let finishWindow = "FinishWindow"   
}

1. 这个演员表并不安全：

   if (segue.identifier == "PopUp2") {
       let vc1 = segue.destination as! CorrectInfoPopUp2
       vc1.InformationRoundNumber = oldQNumber
   }
   

这样写会更好一点：

    if segue.identifier == SegueIdentifiers.popUp, let vc = segue.destination as? CorrectInfoPopUp2 {
        vc.InformationRoundNumber = questionNumber
    }

1. 如果您使用 swift 4.2，您可以使用 Int.random(0..<allQuestions2.list.count) 而不是 Int(arc4random_uniform(UInt32(allQuestions2.list.count)))

附：如果您对如何编写更具可读性的代码感兴趣，可以查看Raywenderlich's Swift Style Guide 示例。

Answer 2

在newNumber 方法中，您分配了questionNumber，但在为segue 做准备时，您将oldQNumber 分配为vc1 的变量。因为你在调用newNumber之后并没有改变oldQNumber，所以我猜你想通过questionNumber

vc1.InformationRoundNumber = questionNumber