Swift 我可以使用willSet和/或didSet根据变量值触发到新视图控制器的转换吗？

我是编程新手，今天我一直在研究Swift中的房地产观察家。这让我想知道，当变量的值达到某一点时，是否可以使用一个变量触发应用程序更改屏幕

例如，假设我有一个游戏，它使用变量“score”来保存和加载用户的分数。我可以使用willSet或didSet根据分数将达到某个值的事实触发视图的更改吗

我当时想的是这样的：

var maxscore : Int = 0 {
    didSet{
        if maxscore == 5{
        switchScreen()

        }}
}

。。。将调用开关屏幕功能。这样行吗？我还没有找到任何关于这方面的信息，所以不知道这是因为不可能，还是因为我没有找到它

但是我尝试过，但没有成功。它可以编译和运行，但是当分数达到5这个神奇的数字时，什么也没有发生

为完整起见，我的开关屏幕功能代码如下：

func switchScreen() {
    let mainStoryboard = UIStoryboard(name: "Storyboard", bundle: NSBundle.mainBundle())
    let vc : UIViewController = mainStoryboard.instantiateViewControllerWithIdentifier("HelpScreenViewController") as UIViewController
    self.presentViewController(vc, animated: true, completion: nil)
}

func CheckAnswer( answerNumber : Int)
{
    if(answerNumber == currentCorrectAnswerIndex)
    {
        // we have the correct answer
        labelFeedback.text = "Correct!"
        labelFeedback.textColor = UIColor.greenColor()
        score = score + 1
        labelScore.text = "Score: \(score)"

        totalquestionsasked = totalquestionsasked + 1
        labelTotalQuestionsAsked.text = "out of \(totalquestionsasked)"

        if score == 5 { maxscore = 5}
        // later we want to play a "correct" sound effect
        PlaySoundCorrect()
      }
    else
    {
        // we have the wrong answer
        labelFeedback.text = "Wrong!"
        labelFeedback.textColor = UIColor.blackColor()

        totalquestionsasked = totalquestionsasked + 1
        labelTotalQuestionsAsked.text = "out of \(totalquestionsasked)"

        if score == 5 { maxscore = 5}
        // we want to play a "incorrect" sound effect
        PlaySoundWrong()
    }

    SaveScore()
    buttonNext.enabled = true
    buttonNext.hidden = false
}

我用于将值设置为5的代码如下：

func switchScreen() {
    let mainStoryboard = UIStoryboard(name: "Storyboard", bundle: NSBundle.mainBundle())
    let vc : UIViewController = mainStoryboard.instantiateViewControllerWithIdentifier("HelpScreenViewController") as UIViewController
    self.presentViewController(vc, animated: true, completion: nil)
}

func CheckAnswer( answerNumber : Int)
{
    if(answerNumber == currentCorrectAnswerIndex)
    {
        // we have the correct answer
        labelFeedback.text = "Correct!"
        labelFeedback.textColor = UIColor.greenColor()
        score = score + 1
        labelScore.text = "Score: \(score)"

        totalquestionsasked = totalquestionsasked + 1
        labelTotalQuestionsAsked.text = "out of \(totalquestionsasked)"

        if score == 5 { maxscore = 5}
        // later we want to play a "correct" sound effect
        PlaySoundCorrect()
      }
    else
    {
        // we have the wrong answer
        labelFeedback.text = "Wrong!"
        labelFeedback.textColor = UIColor.blackColor()

        totalquestionsasked = totalquestionsasked + 1
        labelTotalQuestionsAsked.text = "out of \(totalquestionsasked)"

        if score == 5 { maxscore = 5}
        // we want to play a "incorrect" sound effect
        PlaySoundWrong()
    }

    SaveScore()
    buttonNext.enabled = true
    buttonNext.hidden = false
}

---

这是因为方法在类中，而不是您应该能够做到的！。检查答案

//True model data
var _test : Int = 0 {

//First this
willSet {
    println("Old value is \(_test), new value is \(newValue)")
}

//value is set

//Finaly this
  didSet {
     println("Old value is \(oldValue), new value is \(_test)")
  }
}

---

谢谢你的推荐。那里有很多信息-你认为我应该特别关注什么？