ios - Swift : property 'self.circle1' not initialized at super. 初始化调用出错？

Question

我是编程新手，正在尝试用 Swift 编写一个井字游戏应用程序，但这个错误使我无法运行该应用程序:属性“self.circle1”未在 super.init 调用时初始化。

该应用程序尚未完成，但我看不到现有代码中的错误所在。请再次彻底解释任何建议，因为我是初学者。谢谢!我的代码:

import UIKit

class ViewController: UIViewController {

    //Initializing all imgs as variables:

    @IBOutlet strong var circle1: UIImageView
    @IBOutlet strong var circle2: UIImageView
    @IBOutlet strong var circle3: UIImageView
    @IBOutlet strong var circle4: UIImageView
    @IBOutlet strong var circle5: UIImageView
    @IBOutlet strong var circle6: UIImageView
    @IBOutlet strong var circle7: UIImageView
    @IBOutlet strong var circle8: UIImageView
    @IBOutlet strong var circle9: UIImageView

    @IBOutlet strong var circleBtn1: UIButton
    @IBOutlet strong var circleBtn2: UIButton
    @IBOutlet strong var circleBtn3: UIButton
    @IBOutlet strong var circleBtn4: UIButton
    @IBOutlet strong var circleBtn5: UIButton
    @IBOutlet strong var circleBtn6: UIButton
    @IBOutlet strong var circleBtn7: UIButton
    @IBOutlet strong var circleBtn8: UIButton
    @IBOutlet strong var circleBtn9: UIButton

    @IBOutlet strong var resetBtn: UIButton
    @IBOutlet strong var ResultsLabel: UILabel

    //Creating variables:

    var plays = Dictionary<Int,Int>()
    var done = false
    var aiDeciding = false

    //Function that says what to do if a UIButton is clicked:

    @IBAction func UIbuttonClicked(sender:UIButton) {
        ResultsLabel.hidden = true
        if !plays[sender.tag] && !aiDeciding && !done {
        setImgforCircle(sender.tag, player:1)

        }

    //Executing these functions:

        checkforWin()
        aiTurn()

    }

    //Function that sets an X or O in the proper circle depending on player:

    func setImgforCircle(spot:Int, player:Int) {
        var playerMark = player == 1 ? "x" : "o"
        plays[spot] = player
        switch spot {
        case 1:
            circle1.image = UIImage(named: playerMark)
        case 2:
            circle2.image = UIImage(named: playerMark)
        case 3:
            circle3.image = UIImage(named: playerMark)
        case 4:
            circle4.image = UIImage(named: playerMark)
        case 5:
            circle5.image = UIImage(named: playerMark)
        case 6:
            circle6.image = UIImage(named: playerMark)
        case 7:
            circle7.image = UIImage(named: playerMark)
        case 8:
            circle8.image = UIImage(named: playerMark)
        case 9:
            circle9.image = UIImage(named: playerMark)

        default:
            circle2.image = UIImage(named: playerMark)
        }

    }

    //Function that sees if certain paths of circles have the same mark

    func checkforWin() {
    var whoWon = ["Lost":0, "Won":1]
        for (key,value) in whoWon {
            if ((plays[1] == value && plays[2] == value && plays[3] == value) || //across top row
            (plays[4] == value && plays[5] == value && plays[6] == value) || //across middle row
            (plays[7] == value && plays[8] == value && plays[9] == value) || //across bottom row
            (plays[1] == value && plays[4] == value && plays[7] == value) || //down left column
            (plays[2] == value && plays[5] == value && plays[8] == value) || //down middle column
            (plays[3] == value && plays[6] == value && plays[9] == value) || //down right column
            (plays[1] == value && plays[5] == value && plays[9] == value) || //diagonal going right
            (plays[7] == value && plays[5] == value && plays[3] == value)) { //diagonal going left

                ResultsLabel.hidden = false
                ResultsLabel.text = "You \(key)!"
            }

        }

    }
    func aiTurn() {

    }


    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

只需在声明末尾添加问号或感叹号即可:

@IBOutlet strong var circle1: UIImageView?

在 Swift 中，每个变量都必须在调用 super.init 之前进行初始化。在这种情况下，直到加载 Storyboard 或 nib 时才会初始化变量，这将在调用类的 init 方法之后进行。

你的 circle1 变量的类型；除了是一个 UIImageView；将是可选的，因此需要在其声明中指明。因此，您需要打开变量以使用问号或感叹号访问它的值。

let prax = circle1?.image

或

if circle1 {   // now you're sure the object exists
   let prax = circle1!.image
}

(Xcode6 Beta-4 似乎已经解决了这个问题，并自动在代码编辑器中给出“点击修复”错误按钮。)