ios - 如何让我的倒数计时器重置为每次加载 View ？

在我的iOS测试应用程序中，你可以用15秒来回答一个问题。如果回答正确，则第二个视图控制器将出现，而不是通过单击第二个视图控制器上的按钮而被解除，并且第一个视图控制器将重新出现，并出现一个待回答的新问题。但是，只要单击问题的答案，倒计时计时器就会启动，而不是单击第二个视图控制器上的按钮以关闭第二个视图控制器。我希望第二个视图控制器上的按钮被取消后，倒计时计时器立即重置，并用一个新问题显示原始视图控制器。最好的办法是什么？
这是我的代码（第一个视图控制器）：

import UIKit

extension ViewController: QuizCompletedDelegate {
    func continueQuiz() {
        questionTimer.text = String(counter)
    }
}

class ViewController: UIViewController {

    //random image func
    func randomImage() {
        index = Int(arc4random_uniform(UInt32(questionImages.count)))
        questionImage.image = questionImages[index]
    }

    var questionList = [String]()

    func updateCounter() {
        counter -= 1
        questionTimer.text = String(counter)

        if counter == 0 {
            timer.invalidate()
            wrongSeg()
        }
    }

    func randomQuestion() {
        //random question
        if questionList.isEmpty {
            questionList = Array(QADictionary.keys)
            continueQuiz()
        }

        let rand = Int(arc4random_uniform(UInt32(questionList.count)))
        questionLabel.text = questionList[rand]

        //matching answer values to go with question keys
        var choices = QADictionary[questionList[rand]]!

        questionList.remove(at: rand)

        //create button
        var button:UIButton = UIButton()

        //variables
        var x = 1
        rightAnswerBox = arc4random_uniform(4)+1

        for index in 1...4
        {
            button = view.viewWithTag(index) as! UIButton

            if (index == Int(rightAnswerBox))
            {
                button.setTitle(choices[0], for: .normal)
            }
            else {
                button.setTitle(choices[x], for: .normal)
                x += 1
            }
            randomImage()
            continueQuiz()
        }
    }

    let QADictionary = ["Who is Thor's brother?" : ["Atum", "Loki", "Red Norvell", "Kevin Masterson"], "What is the name of Thor's hammer?" : ["Mjolinr", "Uru", "Stormbreaker", "Thundara"], "Who is the father of Thor?" : ["Odin", "Sif", "Heimdall", "Balder"]]

    //wrong view segue
    func wrongSeg() {
        performSegue(withIdentifier: "incorrectSeg", sender: self)
    }

    //proceed screen
    func rightSeg() {
        performSegue(withIdentifier: "correctSeg", sender: self)
    }

    //variables
    var rightAnswerBox:UInt32 = 0
    var index = 0

    //Question Label
    @IBOutlet weak var questionLabel: UILabel!

    //Answer Button
    @IBAction func buttonAction(_ sender: AnyObject) {
        if (sender.tag == Int(rightAnswerBox))
        {
            rightSeg()
            print ("Correct!")
        }

        if counter != 0 {

        }
        else if (sender.tag != Int(rightAnswerBox)) {
            wrongSeg()
            print ("Wrong!")
            timer.invalidate()
            questionList = []
        }
    }

    override func viewDidAppear(_ animated: Bool)
    {
        randomQuestion()
    }

    //variables
    var counter = 15

    var timer = Timer()

    @IBOutlet weak var questionTimer: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        timer = Timer.scheduledTimer(timeInterval: 1, target:self, selector: #selector(ViewController.updateCounter), userInfo: nil, repeats: true)
    }

第二个视图控制器的代码：

import UIKit

protocol QuizCompletedDelegate {
    func continueQuiz()
}

class ContinueScreen: UIViewController {

    var delegate: QuizCompletedDelegate?

    //correct answer label
    @IBOutlet weak var correctLbl: UILabel!

    //background photo
    @IBOutlet weak var backgroundImage: UIImageView!

    func backToQuiz() {
        if let nav = self.navigationController {
            nav.popViewController(animated: true)
        }
        else {
            self.dismiss(animated: true, completion: nil)
        }
    }

    @IBAction func `continue`(_ sender: Any) {
        backToQuiz()
        delegate?.continueQuiz()
    }

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

最佳答案

您可以在第一个视图控制器上实现函数viewDidAppear（），当您的第二个视图控制器被解除时，该函数将自动调用，因此第一个视图控制器将被再次看到。
因此，在第一个视图控制器中创建此函数：

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    // HERE PUT YOUR TIMER RESET
    // ...
}

关于ios - 如何让我的倒数计时器重置为每次加载 View ？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/45382936/