iOS: Hide the navigation bar for only one viewcontroller which is root of the UINavigationController?

Question

I want to hide the navigationbar for only one viewcontroller which is the root viewcontroller of the UINavigationController.

Currently I am using below code to hide the navigation bar for a particular viewcontroller.

To hide the navigationbar,

    override func viewWillAppear(_ animated: Bool) {
        self.navigationController?.isNavigationBarHidden = true
        super.viewWillAppear(animated)
    }

To show the navigationbar for other viewcontrollers,

    override func viewWillDisappear(_ animated: Bool) {
        self.navigationController?.isNavigationBarHidden = false
        super.viewWillDisappear(animated)
    }

When I am trying to use this code, the app is being crashed in iOS 13 devices because of threading violation: expected the main thread.

Please checkout the issue which I am getting when I use the above code to hide the navigationbar,

iOS 13: threading violation: expected the main thread

Please let me know if there is any other way to hide the navigationbar for only one viewcontroller.

You already asked this question once [here](https://stackoverflow.com/q/58335061/5215625). Don't ask multiple times about the same problem. Close this question. — Starsky, Oct 11 '19 at 08:29

score 9 · Accepted Answer · answered Oct 12 '19 at 04:40

I got the another way to hide/show navigationbar from one of my friend.

Set a delegate for the NavigationController:

navigationController.delegate = self

Hide/Show navigationbar for each ViewController all in one place

func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
    let hide = (viewController is YourVC)
    navigationController.setNavigationBarHidden(hide, animated: animated)
}

score 6 · Answer 2 · answered Oct 11 '19 at 09:08

import UIKit
 class ViewController: UIViewController {

 override func viewWillAppear(_ animated: Bool){
    super.viewWillAppear(animated)
    self.navigationController?.isNavigationBarHidden = true
   }
 override func viewWillDisappear(_ animated: Bool){
    super.viewWillDisappear(animated)
    self.navigationController?.isNavigationBarHidden = false
   }

}

score 1 · Answer 3 · answered Oct 11 '19 at 08:57

You can make it transparent (Completely invisible) when viewWillApper get called and back to normal when view willDisappear get called. Here are helper functions.


func makeNaBarTransparent() {
      navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
      navigationController?.navigationBar.shadowImage = UIImage()
      navigationController?.navigationBar.isTranslucent = true
  }


 func restoreNavigationBarToDefault() {
      navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
      navigationController?.navigationBar.shadowImage = nil
  }

USAGE

 import UIKit
class ViewController: UIViewController {

 override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        makeNaBarTransparent()
    }

 override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        restoreNavigationBarToDefault()
    }

}

iOS: Hide the navigation bar for only one viewcontroller which is root of the UINavigationController?

3 Answers3