iOS事件传递 -- 如何让view响应超出边界的事件

iOS中事件响应会先依次调用个层级view的[UIView pointInSide] 方法, 如果返回true, 则会走改view的hittest方法, 所以如果我们想让view或者它的子view响应超出它的frame的点击事件, 则需要让view的pointInside方法返回为true, 然后在hittest方法中通过转换坐标的方法, 来选择我们想要处理该事件的targetView, 调用targetView.hittest方法, 即可.

案例:

1. cell上的子view想要响应其frame以外的点击事件, 此处注意子view是加在contentView上的

extension BigImageCell {
    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {

        for subv in self.contentView.subviews {
            let newP = subv.convert(point, from: self.contentView)
            if subv.bounds.contains(newP) {
                return subv.hitTest(newP, with: event)
            }
        }

        return super.hitTest(point, with: event)
    }
    
    override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        for subv in self.contentView.subviews {
            let localPoint = subv.convert(point, from: self.contentView)
            if subv.bounds.contains(localPoint) {
                return true
            }
        }
        return super.point(inside: point, with: event)
    }
}