ios - 在运行的动画中检索点击的 UIButton，它可以稍微离开屏幕

Question

这就是代码(下面)的样子:

import UIKit

class TornadoButton: UIButton {

    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let pres = self.layer.presentation()!
        let suppt = self.convert(point, to: self.superview!)
        let prespt = self.superview!.layer.convert(suppt, to: pres)

        return super.hitTest(prespt, with: event)
    }
}

class TestViewController: UIViewController {

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        let greySubview = UIView()
        greySubview.backgroundColor = .red
        greySubview.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(greySubview)

        greySubview.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        greySubview.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
        greySubview.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
        greySubview.heightAnchor.constraint(equalTo: greySubview.widthAnchor).isActive = true

        let button = TornadoButton()
        greySubview.addSubview(button)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.widthAnchor.constraint(equalTo: greySubview.widthAnchor, multiplier: 0.09).isActive = true
        button.heightAnchor.constraint(equalTo: greySubview.heightAnchor, multiplier: 0.2).isActive = true

        //below constrains are needed, else the origin of the UIBezierPath is wrong
        button.centerXAnchor.constraint(equalTo: greySubview.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: greySubview.centerYAnchor, constant: self.view.frame.height * 0.35).isActive = true
        self.view.layoutIfNeeded()

        button.addTarget(self, action: #selector(tappedOnCard(_:)), for: .touchUpInside)

        let circlePath = UIBezierPath(arcCenter: greySubview.frame.origin, radius: CGFloat(greySubview.frame.width * 0.5), startAngle: 0, endAngle: CGFloat.pi * 2, clockwise: true)

        let orbit = CAKeyframeAnimation(keyPath: "position")
        orbit.duration = 12
        orbit.path = circlePath.cgPath
        orbit.isAdditive = true
        orbit.repeatCount = Float.greatestFiniteMagnitude
        orbit.calculationMode = kCAAnimationPaced
        orbit.rotationMode = kCAAnimationRotateAuto

        button.layer.add(orbit, forKey: "orbit")
        button.backgroundColor = .blue

        let gr = UITapGestureRecognizer(target: self, action: #selector(onTap(gesture:)))
        greySubview.addGestureRecognizer(gr)
    }

    @objc func onTap(gesture:UITapGestureRecognizer) {
        let p = gesture.location(in: gesture.view)
        let v = gesture.view?.hitTest(p, with: nil)
    }

    @IBAction func tappedOnCard(_ sender: UIButton) {
        print(sender)
    }
}

这几乎可以工作，但是:

如果按钮在屏幕上 100% 可见，我可以检索按钮。例如，如果 50% 可见(并且 50% 离开屏幕(见下图))，我不会检索按钮点击(也不会检索打印)。

当按钮处于正在运行的动画中并且它可以稍微离开屏幕时，如何检索按钮？

Answer 1

原始答案:

很可能是 greySubview 中的 UITapGestureRecognizer 正在消耗触摸，而不是让它传递到按钮。试试这个:

gr.cancelsTouchesInView = NO;

在将 UITapGestureRecognizer 添加到 greySubview 之前。

---

编辑后的答案:

请忽略我之前的回答，如果您这样做了，请恢复更改。我最初的回答没有意义，因为在您的情况下，按钮是 grayView 的 subview ，而 cancelsTouchesInView 在 View 层次结构中向上工作，而不是向下工作。

经过大量挖掘，我能够弄清楚为什么会这样。这是因为在动画期间 TornadoButton 中的 HitTest 不正确。由于您正在为按钮设置动画，因此您需要覆盖 TornadoButton 的 hitTest 和 pointInside 方法，以便它们说明动画位置而不是点击测试时按钮的实际位置。

pointInside 方法的默认实现不考虑按钮的动画表示层，而只是尝试检查矩形内的触摸点(这将失败，因为触摸是别的地方)。

这些方法的以下实现似乎可以解决问题:

class TornadoButton: UIButton{
    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let pres = self.layer.presentation()!
        let suppt = self.convert(point, to: self.superview!)
        let prespt = self.superview!.layer.convert(suppt, to: pres)
        if (pres.hitTest(suppt)) != nil{
            return self
        }
        return super.hitTest(prespt, with: event)
    }

    override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        let pres = self.layer.presentation()!
        let suppt = self.convert(point, to: self.superview!)
        return (pres.hitTest(suppt)) != nil
    }
}