Question

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    let touch = touches.anyObject() as UITouch
    let touchLocation = touch.locationInNode(self)

    timer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: "shoot", userInfo: touchLocation, repeats: true) // error 1
}

func shoot() {
    var touchLocation: CGPoint = timer.userInfo // error 2
    println("running")
}

我正在尝试创建一个定期运行的计时器，它将触摸点（CGPoint）作为userInfo传递给NSTimer，然后通过shoot（）函数访问它。但是，现在我收到的错误是

1）调用中的额外参数选择器

2）无法转换表达式AnyObject？致CGPoint

现在我似乎无法将userInfo传递给另一个函数然后检索它。

Answer 1

不幸的是CGPoint不是一个对象（至少在Objective-C世界中，Cocoa API起源于此）。它必须包装在NSValue对象中以放入集合中。

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    let touch = touches.anyObject() as UITouch
    let touchLocation = touch.locationInNode(self)
    let wrappedLocation = NSValue(CGPoint: touchLocation)

    timer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: "shoot:", userInfo: ["touchLocation" : wrappedLocation], repeats: true)
}

func shoot(timer: NSTimer) {
    let userInfo = timer.userInfo as Dictionary<String, AnyObject>
    var touchLocation: CGPoint = (userInfo["touchLocation"] as NSValue).CGPointValue()
    println("running")
}

Swift NSTimer将userInfo检索为CGPoint

1 个答案: