ios - 在Swift中开始覆盖

Question

我覆盖:

override func touchesBegan(touches: NSSet, withEvent event: UIEvent)

在Swift中。

我想知道，这对于获得一个接触点是否正确:

var touchPoint: CGPoint! = event.touchesForView(self)?.anyObject()?.locationInView(self)

提前致谢!

Answer 1

从iOS 8.3开始，touchesBegan带有touches参数，它是Set<NSObject>。现在是Set<UITouch>。因此，您将:

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let point = touches.first?.location(in: view) else { return }

    // use `point` here
}

在先前的iOS版本中，如问题所述， touchesBegan被定义为 NSSet参数，因此您将:

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    if let touch = touches.anyObject() as? UITouch {
        let touchPoint = touch.locationInView(view)
        ...
    }
}