UINavigationBar change colors on push

Question

I\'m using 2 different bar tint colors at UINavigationBar in different views. I\'n changing color with that method in both views:

override func          


        

Answer 1

I am just wondering. For the same purpose I use UINavigationControllerDelegate. In navigationController(_:willShow:) I start the animation using transitionCoordinator?.animate(alongsideTransition:completion:). It works great when pushing new controllers, however pop doesn't.

func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
  let dst = viewController as! ViewController
  guard animated else {
    navigationController.navigationBar.barTintColor = dst.navigationBarColor
    navigationController.navigationBar.tintColor = dst.tintColor
    navigationController.navigationBar.barStyle = dst.barStyle
    return
  }

  navigationController.transitionCoordinator?.animate(alongsideTransition: { context in
    navigationController.navigationBar.barTintColor = dst.navigationBarColor
    navigationController.navigationBar.tintColor = dst.tintColor
    navigationController.navigationBar.barStyle = dst.barStyle
  }, completion: { context in
    if context.isCancelled {
      let source = context.viewController(forKey: UITransitionContextViewControllerKey.from) as! ViewController
        navigationController.navigationBar.barTintColor = source.navigationBarColor
        navigationController.navigationBar.tintColor = source.tintColor
        navigationController.navigationBar.barStyle = source.barStyle
    }
})

Do you see any reason why it should work with pushes but not pops?