UINavigationController remove drop shadow when transitioning to another VC - ios

Question

When using a UINavigationController and pushViewController:animated: to push another view controller onto the stack, there is always a drop shadow shown during the transition:
I have an app where I have a video background on the navigation controller, so I want to remove that drop shadow since it looks strange during the transition.
Is there any way to completely remove it? (I am NOT talking about UINavigationBar shadow)

Answer 1

Solution:
// set one of viewcontrollers (usual first) as navigationController delegate
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.delegate = self
}
}
// make the view controller conform to `UINavigationControllerDelegate`
extension ViewController: UINavigationControllerDelegate {
func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return PushPopAnimator(operation: operation)
}
}
// The animation controller
class PushPopAnimator: NSObject, UIViewControllerAnimatedTransitioning {
let operation: UINavigationControllerOperation
init(operation: UINavigationControllerOperation) {
self.operation = operation
super.init()
}
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.25
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let from = transitionContext.viewController(forKey: .from)!
let to = transitionContext.viewController(forKey: .to)!
let rightTransform = CGAffineTransform(translationX: transitionContext.containerView.bounds.size.width, y: 0)
let leftTransform = CGAffineTransform(translationX: -transitionContext.containerView.bounds.size.width, y: 0)
if operation == .push {
to.view.transform = rightTransform
transitionContext.containerView.addSubview(to.view)
UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
from.view.transform = leftTransform
to.view.transform = .identity
}, completion: { finished in
from.view.transform = .identity
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
} else if operation == .pop {
to.view.transform = leftTransform
transitionContext.containerView.insertSubview(to.view, belowSubview: from.view)
UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
to.view.transform = .identity
from.view.transform = rightTransform
}, completion: { finished in
from.view.transform = .identity
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
}
}
}