How to hide navigationBar when scrolling collectionView in ios 11?

Question

In iOS 11 searchBar hides when scrolling tableView if we set to hide. how can I hide searchBar, navigationBar and tabBar when scrolling collectionView up ? And unhide them all when scrolling down ? Thanks for your help...

Answer 1

1. Subclass UIScrollViewDelegate in your UIViewController (i.e. class ViewController: UIViewController, UIScrollViewDelegate { codes... })

2. Implement scrollViewDidScroll Delegate method

   func scrollViewDidScroll(scrollView: UIScrollView) { 
       let pan = scrollView.panGestureRecognizer
       let velocity = pan.velocityInView(scrollView).y
       if velocity < -5 { 
           self.navigationController?.setNavigationBarHidden(true, animated: true) 
           self.navigationController?.setToolbarHidden(true, animated: true)
       } else if velocity > 5 {
           self.navigationController?.setNavigationBarHidden(false, animated: true)
           self.navigationController?.setToolbarHidden(false, animated: true)
       }
   }