Swift NSTimer 将 userInfo 检索为 CGPoint [英] Swift NSTimer retrieving userInfo as CGPoint

问题描述

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，该计时器将触摸点 (CGPoint) 作为 userInfo 传递给 NSTimer，然后通过 shot() 函数访问它.但是，现在我收到一个错误，内容为

I am trying to create a timer that runs periodicly that passes the touched point (CGPoint) as userInfo to the NSTimer and then accessing it over at the shoot() function. However, right now I am getting an error that says

1) 调用中的额外参数选择器

1) extra argument selector in call

2) 不能转换表达式类型 AnyObject?到 CGPoint

2) cannot convert expression type AnyObject? To CGPoint

现在我似乎无法将 userInfo 传递给另一个函数然后检索它.

Right now I can't seem to pass the userInfo over to the other function and then retrieving it.

推荐答案

不幸的是 CGPoint 不是一个对象(至少在 Cocoa API 起源于 Objective-C 的世界中).它必须包装在 NSValue 对象中才能放入集合中.

Unfortunately CGPoint is not an object (at least in Objective-C world, from which Cocoa APIs originate). It has to be wrapped in a NSValue object to be put in a collection.

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")
}

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