ios - 将枚举变量转换为 anyObject - ios with swift

Question

让我解释一下我的代码，然后说明我面临的问题

我有两个 viewControllers 类

1- difficultyViewController:用户选择游戏难度的地方

**difficultyViewController 有三个按钮供用户点击所需的难度

2- gameViewController :将游戏呈现给用户的地方**目前在gameViewController中只有一个label

在 difficultyViewController 中我有一个代表三个游戏难度的枚举

class difficultyViewController: UIViewController {

    enum difficulties {
        case Easy
        case Medium
        case Hard
    }
     var gameDifficulty : difficulties?
    // other code is here
}

在 gameViewController 中我有一个变量对应于这个枚举

class gameViewController: UIViewController {

    @IBOutlet weak var gameDifficultyLabel: UILabel!
    var gameDifficulty : difficultyViewController.difficulties?
    // other code is here
} 

在 difficultyViewController 中，我使用代码来执行和准备 segue

@IBAction func easyButtonPressed(sender: AnyObject) {
        gameDifficulty = .Easy
        performSegueWithIdentifier("toGame", sender: gameDifficulty as? AnyObject)
    } 

这是准备segue的代码

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "toGame" {
            if let gameVC = segue.destinationViewController as? gameViewController {
                if let difficulty = sender as? difficulties {
                    print(difficulty)
                    gameVC.gameDifficulty = difficulty
                }
            }
        }
    }

现在我面临的问题是当将难度作为参数发送给 perform segue 时，从枚举变量到无效的转换，我总是收到一个 nil 值

这是什么原因？无法将枚举转换为 anyObject 吗？

Answer 1

您是在用户按下按钮时设置游戏难度变量，那么为什么不直接根据该值设置难度级别呢？

此外，您的类名和枚举名应该大写，以区别于变量名。

class DifficultyViewController: UIViewController {

    enum Difficulties {
        case Easy
        case Medium
        case Hard
    }
     var gameDifficulty : Difficulties?
    // other code is here
}

class GameViewController: UIViewController {

    @IBOutlet weak var gameDifficultyLabel: UILabel!
    var gameDifficulty : DifficultyViewController.Difficulties?
    // other code is here
} 


@IBAction func easyButtonPressed(sender: AnyObject) {
        gameDifficulty = .Easy
        performSegueWithIdentifier("toGame", sender: AnyObject)
}




override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "toGame" {
            if let gameVC = segue.destinationViewController as? gameViewController {
                    gameVC.gameDifficulty = gameDifficulty // You changed this in the IBAction, so simply send it on to the next VC
                }
            }
        }
}