将手势识别器添加到屏幕外的元素

Question

我有一个比我的设备屏幕宽两倍的视图，并且有可以左右移动视图的滑动手势识别器。但我开始意识到，如果在最初不在屏幕上的视图部分执行滑动操作，视图将不会执行手势操作。

// View twice as wide as the device screen
let masterView = UILabel(frame: CGRect(x: 0, y: 0, width: self.view.frame.width * 2, height: 100))

let swipeLeftGesture = UISwipeGestureRecognizer(target: self, action: #selector(ThisViewController.swipeLeft))
let swipeRightGesture = UISwipeGestureRecognizer(target: self, action: #selector(ThisViewController.swipeRight))
swipeLeftGesture.direction = UISwipeGestureRecognizerDirection.left
swipeRightGesture.direction = UISwipeGestureRecognizerDirection.right
masterView.addGestureRecognizer(swipeLeftGesture)
masterView.addGestureRecognizer(swipeRightGesture)
self.addSubview(masterView)


func swipeLeft() {        
    // Moves masterView to the left equal to that of the width of the screen (or half of masterView's total width)
    let moveLeftFrame = CGRect(x: (masterView.frame.width / 2) * -1, y: masterView.frame.minY, width: masterView.frame.width, height: masterView.frame.height)

    UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: .calculationModeCubic, animations: {
        UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.4, animations: {
            masterView.frame = moveLeftFrame
        })
    }, completion: { (true) in

    })
}


func swipeRight() {        
    // Moves masterView back to original location
    let moveRightFrame = CGRect(x: 0, y: masterView.frame.minY, width: masterView.frame.width, height: masterView.frame.height)

    UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: .calculationModeCubic, animations: {
        UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.4, animations: {
            masterView.frame = moveRightFrame
        })
    }, completion: { (true) in

    })
}

因此，在向左滑动以查看视图的另一半（在屏幕外加载）后，我无法向右滑动。不能在屏幕外加载的位置上执行手势吗？

编辑：所以在稍微修改之后，我发现在屏幕外加载的视图的任何位置都无法识别手势。因此，如果我移动视图以查看从屏幕外开始的 50 像素，则无法在这 50 像素上识别手势。

Answer 1

我不太明白你的回答，但希望这会有所帮助

所以我认为你的问题是

1. 您声明滑动功能的方式是错误的。而不是 func swipeLeft() 将其更改为 func swipeLeft(sender: UISwipeGestureRecognizer)

或

1. 问题可能出在您声明框架变量的方式上。您可以在我的代码中查看更改的内容。

.code.

func swipeLeft(sender: UISwipeGestureRecognizer) {        
    // Moves masterView to the left equal to that of the width of the screen (or half of masterView's total width)
    let moveLeftFrame = CGRect(x: -view.frame.width, y: 0, width: masterView.frame.width, height: masterView.frame.height)

    UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: .calculationModeCubic, animations: {
        UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.4, animations: {
            masterView.frame = moveLeftFrame
        })
    }, completion: { (true) in

    })
}

func swipeRight(sender: UISwipeGestureRecognizer) {        
    // Moves masterView back to original location
    let moveRightFrame = CGRect(x: 0, y: 0, width: masterView.frame.width, height: masterView.frame.height)

    UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: .calculationModeCubic, animations: {
        UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.4, animations: {
            masterView.frame = moveRightFrame
        })
    }, completion: { (true) in

    })
}