ios - 如何从外部访问for循环并使其 swift 停止

Question

我正在使用这个函数让文本一个字母一个字母地写:

extension SKLabelNode {

func setTextWithTypeAnimation(typedText: String, characterInterval: NSTimeInterval = 0.05) {
    text = ""
    self.fontName = "PressStart2P"
    dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0)) {
        for character in typedText.characters {
            dispatch_async(dispatch_get_main_queue()) {
                self.text = self.text! + String(character)
            }
            NSThread.sleepForTimeInterval(characterInterval)
        }
    }
}

而且，如果用户点击屏幕，我想让 for 循环停止并立即显示完整的文本。

Answer 1

我会做这样的事情:

var ignoreSleeper = false    

@IBAction func pressButton(sender: UIButton) {
        ignoreSleeper = true
}

extension SKLabelNode {

func setTextWithTypeAnimation(typedText: String, characterInterval: NSTimeInterval = 0.05) {
    text = ""
    self.fontName = "PressStart2P"
    dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0)) {
        for character in typedText.characters {
            dispatch_async(dispatch_get_main_queue()) {
                self.text = self.text! + String(character)
            }
            if(!ignoreSleeper){
            NSThread.sleepForTimeInterval(characterInterval)
            }
        }
    }
}

编辑:就像@Breek 已经提到的