ios - 如何在两个单独的 View Controller 上跟踪数组的元素？

Question

我正在开发一个测验应用程序，在第一个 UIViewController 上，系统会向用户提出一个问题，并给出四个按钮作为答案。如果他们得到正确的答案，则该元素将从要问的问题数组中删除。但是，如果我对另一个 View Controller 实现一个 segue，当它返回到第一个 View Controller 询问另一个问题时询问用户是否要继续，该数组将重新填充用户已经回答的问题，即使他们应该是删除。我如何确保一旦我转到第二个 View Controller 并从第二个 View Controller 询问用户是否要继续，问题数组不会重新填充已回答的问题？

这是我的代码:

import UIKit

class ViewController: UIViewController {

var questionList = [String]()

func updateCounter() {

    counter -= 1
    questionTimer.text = String(counter)

    if counter == 0 {
        timer.invalidate()
        wrongSeg()
        counter = 15
    }
}


func randomQuestion() {

    //random question
    if questionList.isEmpty {
        questionList = Array(QADictionary.keys)
        questionTimer.text = String(counter)

    }

    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()
        }
    }


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 {
        counter = 15
        questionTimer.text = String(counter)
    }
else if (sender.tag != Int(rightAnswerBox)) {
    wrongSeg()
print ("Wrong!")
    timer.invalidate()
    questionList = []

    }
   randomQuestion()
}

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 View Controller 的代码:

import UIKit

class ContinueScreen: UIViewController {    
//correct answer label
@IBOutlet weak var correctLbl: UILabel!
//background photo
@IBOutlet weak var backgroundImage: UIImageView!

func backToQuiz() {
    performSegue(withIdentifier: "continueSeg", sender: self)
}

@IBAction func `continue`(_ sender: Any) {
    backToQuiz()
}

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

Answer 1

您需要为此实现委托(delegate)。您可以找到更多信息here .

您的问题与this有关.

请仔细阅读。希望有所帮助。