在Swift错误中触摸开始

Question

我正在尝试重载Swift中的touchesBegan函数，但是我遇到了一个奇怪的错误导致XCode崩溃。

我认为问题出在“for touch: AnyObject in touches {”行，但我在其他课程中使用它并且效果很好。

这是我的代码：

import SpriteKit

class PlayScene: SKScene {

    let touchButton = SKSpriteNode(imageNamed:"Touch")
    override func didMoveToView(view: SKView!) {
        self.backgroundColor = UIColor(hex: 0xD64541)
        self.touchButton.size = CGSizeMake(50, 50)
        let touchButtonWidth = self.touchButton.size.width
        let touchButtonHeight = self.touchButton.size.height
        self.touchButton.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
        self.addChild(self.touchButton)
    }
    override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
        for touch: AnyObject in touches {
            let location = touch.locationInNode(self)
            if self.nodeAtPoint(location) == self.touchButton {
                println("button")
            }
            else {
                println("ext")
            }

        }
    }
}

谢谢

Answer 1

在迭代之前尝试检查touches是否为nil（适用于我）：

override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
    if let tchs = touches {
        for touch: AnyObject in tchs {
            let location = touch.locationInNode(self)
            if self.nodeAtPoint(location) == self.touchButton {
                println("button")
            }
            else {
                println("ext")
            }

        }
    }
}