思路就是: 右滑返回優先. 當觸發到右滑返回手勢時就取消 scrollView的手勢css
OC版
ui
[self.contentScrollView.panGestureRecognizer requireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];
Swift版
spa
self.contentScrollView.panGestureRecognizer.requireGestureRecognizerToFail(navigationController!.interactivePopGestureRecognizer!)