iOS 在@selector 处获取 UIButton 当前的 UIControlEventType

Question

let aButton = UIButton()
a.addTarget(self, action: "handler:", forControlEvents: .TouchUpInside)

func handler(btn: UIButton) {
    //Is there anyway can I know the controlEvent is "TouchUpInside" in this method?
}

如上例，我想知道@selector 的ControlEventType，找不到正确的API 或者不可能？

Answer 1

您可以为不同的控件事件提供不同的方法:

a.addTarget(self, action: "touchDownHandler:", forControlEvents: .TouchDown)
a.addTarget(self, action: "touchUpHandler:", forControlEvents: .TouchUpInside)

func touchDownHandler(btn: UIButton) {
}

func touchUpHandler(btn: UIButton) {
}

如 another answer 中所述您还可以在处理程序中获取事件并检查触摸类型，这里是 Swift 中的:

a.addTarget(self, action: "handleTouch:event:", forControlEvents: .AllTouchEvents)

// ...

func handleTouch(button: UIButton, event: UIEvent) {
    if let touch = event.touchesForView(button)?.first as? UITouch {
        switch touch.phase {
        case .Began:
            println("touch began")

        case .Ended:
            println("touch ended")

        case .Moved:
            println("touch moved")

        case .Cancelled:
            println("touch cancelled")

        case .Stationary:
            println("touch stationary")

        }
    }
}