iOS view 点击事件分发处理

当创建自定义view时，如果底层view与上层view（button）都需要处理点击事件时：
继承UIGestureRecognizerDelegate，设置底层view的UITapGestureRecognizer的delegate为self，实现shouldReceive的方法

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    if (touch.view?.isKind(of: self.classForCoder))! {
            return true
    }else{
            return false
    }
}