How to show navigation bar on scroll iOS - ios

Question

I find a lot of resources on how to hide the navigation bar on scroll, but I would like to have the navigation bar hidden on start, and then appear when starting to scroll. Like this animation from Design+Code app: https://imgur.com/a/SqDRD

Answer 1

You can use UIScrollViewDelegate for that.
Here is example code for hide navigation bar and tool bar with scroll:
import UIKit
class ViewController: UIViewController, UIScrollViewDelegate {
#IBOutlet weak var toolBar: UIToolbar!
#IBOutlet weak var webV: UIWebView!
var lastOffsetY :CGFloat = 0
override func viewDidLoad() {
super.viewDidLoad()
webV.scrollView.delegate = self
let url = "http://apple.com"
let requestURL = NSURL(string:url)
let request = NSURLRequest(URL: requestURL!)
webV.loadRequest(request)
}
//Delegate Methods
func scrollViewWillBeginDragging(scrollView: UIScrollView){
lastOffsetY = scrollView.contentOffset.y
}
func scrollViewWillBeginDecelerating(scrollView: UIScrollView){
let hide = scrollView.contentOffset.y > self.lastOffsetY
self.navigationController?.setNavigationBarHidden(hide, animated: true)
toolBar.hidden = hide
}
}

Answer 2

Using the willBeginDragging and didEndDragging you can accomplish what you want. Here there is a simplified version of it, you may need to modify it a little bit to obtain the desired effect you want, but it is an starting point.
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.setNavigationBarHidden(true, animated: false)
}
}
extension ViewController: UIScrollViewDelegate {
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
navigationController?.setNavigationBarHidden(false, animated: true)
}
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
navigationController?.setNavigationBarHidden(true, animated: true)
}
}