Swift - 必須調用超類 SKSpriteNode 錯誤的指定初始值設定項

Question

此代碼在第一個 XCode 6 Beta 上工作，但在最新的 Beta 上它不起作用並出現此類錯誤Must call a designated initializer of the superclass SKSpriteNode ：

import SpriteKit

class Creature: SKSpriteNode {
  var isAlive:Bool = false {
    didSet {
        self.hidden = !isAlive
    }
  }
  var livingNeighbours:Int = 0

  init() {
    // throws: must call a designated initializer of the superclass SKSpriteNode
    super.init(imageNamed:"bubble") 
    self.hidden = true
  }

  init(texture: SKTexture!) {
    // throws: must call a designated initializer of the superclass SKSpriteNode
    super.init(texture: texture)
  }

  init(texture: SKTexture!, color: UIColor!, size: CGSize) {
    super.init(texture: texture, color: color, size: size)
  }
}

這就是這個類的初始化方式：

let creature = Creature()
creature.anchorPoint = CGPoint(x: 0, y: 0)
creature.position = CGPoint(x: Int(posX), y: Int(posY))
self.addChild(creature)

我被它困住了..最簡單的解決方法是什么？

Answer 1

init(texture: SKTexture!, color: UIColor!, size: CGSize)是 SKSpriteNode 類中唯一的指定構造器，其余都是便利構造器，所以不能調用 super 。 將您的代碼更改為：

class Creature: SKSpriteNode {
    var isAlive:Bool = false {
        didSet {
            self.hidden = !isAlive
        }
    }
    var livingNeighbours:Int = 0

    init() {
        // super.init(imageNamed:"bubble") You can't do this because you are not calling a designated initializer.
        let texture = SKTexture(imageNamed: "bubble")
        super.init(texture: texture, color: UIColor.clearColor(), size: texture.size())
        self.hidden = true
    }

    init(texture: SKTexture!) {
        //super.init(texture: texture) You can't do this because you are not calling a designated initializer.
        super.init(texture: texture, color: UIColor.clearColor(), size: texture.size())
    }

    init(texture: SKTexture!, color: UIColor!, size: CGSize) {
        super.init(texture: texture, color: color, size: size)
    }
}

此外，我會將所有這些合並到一個初始值設定項中。

Answer 2

瘋狂的東西..我不完全明白我是如何設法修復它的..但這有效：

convenience init() {
    self.init(imageNamed:"bubble")
    self.hidden = true
}

init(texture: SKTexture!, color: UIColor!, size: CGSize) {
    super.init(texture: texture, color: color, size: size)
}

為init增加convenience並刪除init(texture: SKTexture!)