ios - 无法将类型 'UIView' (0x10d54a4c0) 的值转换为 'UIButton' (0x10d552120)

Question

已经提出了这样的问题，但我尝试了这些建议，但它仍然对我不起作用。 :/

我正在尝试使用本教程制作一个测验应用程序:https://www.youtube.com/watch?v=KNAQ3Y8PGkM&t=1s

这是下载我的项目的链接:https://www.dropbox.com/s/bwvg6fyrrzudued/kat%20quiz.zip?dl=0

一切都很完美，除了我收到错误:

Could not cast value of type 'UIView' (0x10d54a4c0) to 'UIButton' (0x10d552120)

我真的很感激一些帮助。我尝试了我所知道的一切并进行了搜索，谢谢。 :)

    import UIKit

class ViewController: UIViewController {

     let questions = ["What color is Courage the Cowardly Dog?", "What is the name of the woman that lives with Courage?", "What is the name of the man that lives with Courage?"]
     let answers = [["Purple","Grey","Orange"],["Muriel", "Angela", "Elizabeth"], ["Eustace", "Robert", "Ezio"]]

    //Variables
    var currentQuestion = 0
    var rightAnswerPlacement:UInt32 = 0
    var points = 0

    //Label
    @IBOutlet weak var lbl: UILabel!

    //Button
    @IBAction func action(_ sender: AnyObject) {

        if (sender.tag == Int(rightAnswerPlacement))
        {
            print ("RIGHT!")
            points += 1
        }
        else
        {
            print ("WRONG!!!!!!")
        }
        if (currentQuestion != questions.count)
        {
            newQuestion()
        }
        else{
            performSegue(withIdentifier: "showScore", sender: self)
        }
    }

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



    //Function that displays new question
    func newQuestion(){
        lbl.text = questions[currentQuestion]
        rightAnswerPlacement = arc4random_uniform(3)+1

        //Create a button
        var button:UIButton = UIButton()

        var x = 1

        for i in 1...3
        {
            //Create a button
            button = view.viewWithTag(i) as! UIButton

            if (i == Int(rightAnswerPlacement))
            {
                button.setTitle(answers[currentQuestion][0], for: .normal)
            }

            else
            {
                button.setTitle(answers[currentQuestion][x], for: .normal)
                x = 2
            }

        }
        currentQuestion += 1
    }



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

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

Answer 1

您是否在 Storyboard中创建了 UI 按钮？在您的 YouTube 视频中，观看 1:45

记住将 3 个 UI 按钮的标签设置为 1、2 和 3观看 3:20

出现问题是因为您将 View 的标记设置为 = 1。

您可以通过将 View 的标记值更改为数字来轻松修复它!= 1、2 和 3

因为您的 ViewController 有 2 个具有相同标签的 View = 1。(view 和 UI Button)。因此，当您使用 view.viewWithTag(i) 时，它会意外选择 view 而不是 UI Button。所以无法转换为UI Button类型

P/s:下次，如果您想直接选择按钮，您可以像使用 一样为该 Button 创建一个 @IBOutlet标签。它不会导致像这样令人困惑的错误