如何在向下滚动时隐藏导航栏和工具栏？ Swift（如 myBridge 应用程序）

我想在向下滚动页面时隐藏工具栏和导航栏。当我向上滚动时返回它。这怎么可能？

我该如何检测阻力？我是使用平移手势还是滚动视图？

尝试这个简单的方法：经过测试Swift 3

    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

    if(velocity.y>0) {
        //Code will work without the animation block.I am using animation block incase if you want to set any delay to it.
        UIView.animate(withDuration: 2.5, delay: 0, options: UIViewAnimationOptions(), animations: { 
            self.navigationController?.setNavigationBarHidden(true, animated: true) 
            self.navigationController?.setToolbarHidden(true, animated: true)
            print("Hide")
        }, completion: nil)

    } else {
        UIView.animate(withDuration: 2.5, delay: 0, options: UIViewAnimationOptions(), animations: { 
            self.navigationController?.setNavigationBarHidden(false, animated: true)
            self.navigationController?.setToolbarHidden(false, animated: true)
            print("Unhide")
        }, completion: nil)    
      }
   }

Output: Updated

Note:如果您将任何数据从该 VC 传递到另一个嵌入了navigationController.你可能需要unhide the NavigationBar.