Swift:在touchesBegan中使用switch语句

Question

我想清理我touchesBegan(..)的SKScene.我想做一个case语句而不是我的if .. else链.但是,我在实现时遇到错误,这表明我不知道如何在引擎盖下完成相同的操作.

代码之前:

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    for touch: AnyObject in touches {
        let location = touch.locationInNode(self)

        if self.nodeAtPoint(location) === playLabel {
            buildLevelSelect()
        } else if self.nodeAtPoint(location) === aboutLabel {
            createAboutView()
        } else if self.nodeAtPoint(location) === storeLabel {
            createStore()
        }
    }
}

代码之后:点击后,某些标签点击工作,但其他一些引发Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode 0x0)错误:

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    for touch: AnyObject in touches {
        let location = touch.locationInNode(self)

        switch(self.nodeAtPoint(location)){
        case playLabel :
            buildLevelSelect()
        case aboutLabel :
            createAboutView()
        case storeLabel :
            createStore()
        default : break
    }
}

Answer 1

switch如果你想要的===行为如下,你可以编写一种奇怪但看起来很有用的东西:

switch(true){
        case self.nodeAtPoint(location) === playLabel : buildLevelSelect()
        case self.nodeAtPoint(location) === aboutLabel : createAboutView()
        case self.nodeAtPoint(location) === storeLabel : createStore()
        default : break
}

在我看来,这仍然比if-else链更清晰.