同时识别多个手势 shouldRecognizeSimultaneouslyWithGestureRecognizer
新创建一个类继承UIScrollView 实现手势代理方法
self.panGestureRecognizer.delegate = self 只能是 scrollview 否则崩溃
'UIScrollView's built-in pan gesture recognizer must have its scroll view as its delegate

class THMarketScrollView: UIScrollView {

override init(frame:CGRect) {
    super.init(frame:frame)
    self.panGestureRecognizer.delegate = self
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

}
extension THMarketScrollView: UIGestureRecognizerDelegate {
 func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith shouldRecognizeSimultaneouslyWithGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
 }
}

参考 https://www.jianshu.com/p/dc8f64ca18ca
https://www.jianshu.com/p/040772693872
https://www.jianshu.com/p/b88a1f877ffa