Navigation Bar is Black during Custom Unwind Segue

Question

I made a custom UIStoryboardSegue but when it unwinds, it seems to cause my UINavigationBar to go black, then back to it's correct color. See the GIF below.

My custom segue just makes the the new ViewController come down from the top and leave going back up to the top.

Here is the UIStoryboardSegue code:

import UIKit

class SlideDownSegue: UIStoryboardSegue {

var duration: Double = 0.5

override func perform() {

    let screenHeight = UIScreen.main.bounds.size.height
    let toVC = self.destination
    let fromVC = self.source

    toVC.view.transform = CGAffineTransform(translationX: 0, y: -screenHeight)
    UIApplication.shared.keyWindow?.insertSubview(toVC.view, aboveSubview: fromVC.view)

    UIView.animate(withDuration: duration, delay: 0, options: UIViewAnimationOptions.curveEaseInOut, animations: {
        toVC.view.transform = CGAffineTransform.identity
    }, completion: {
        success in
        fromVC.present(toVC, animated: false, completion: nil)
    })
}
}

class UnwindSlideDownSegue: UIStoryboardSegue {

override func perform() {

    let screenHeight = UIScreen.main.bounds.size.height
    let toVC = self.destination
    let fromVC = self.source.parent!

    fromVC.view.superview?.insertSubview(toVC.view, at: 0)

    UIView.animate(withDuration: 0.5, delay: 0, options: UIViewAnimationOptions.curveEaseInOut, animations: {
        fromVC.view.transform = CGAffineTransform(translationX: 0, y: -screenHeight - 100)
    }, completion: {
        success in
        fromVC.dismiss(animated: false, completion: nil)
    })
}
}

If I let the unwind do the default where it just leaves by going to to the bottom of the screen but keep my custom for showing the new View, the UINavigationBar maintains it's correct color, it's only when I used my code provided for unwind that the UINavigationBar goes black during the animation.

Any hints would be much appreciated.

---EDIT---

I played with it a little, if I go into the AppDelegate and change UINavigationBar.appearance().isTranslucent = false to true, I instead get a white background, but then it just appears that the Navigation Bar is suddenly appearing. I'm wondering if it is for some reason being unloaded and then loaded back in once the View Controller is active.

---EDIT 2---

I am sorta able to fix it with a hack. In the AppDelegate inside func application(... didFinishLaunchingWithOptions ...) I added in self.window?.backgroundColor = UIColor.{your color} but all that does is make that black part now appear my color, the Navigation Bar is still disappearing during the segue for some reason.

Answer 1

This is a perfect opportunity to use snapshotView(afterScreenUpdates:). That's how UIKit performs many of their stock transitions (even in UINavigationController) and it's a tremendous way to perform custom transitions, particularly if you want to apply effects. Take a snapshot of the destination (which will have an intact navigation bar), insert it right below the source, perform the animation, dismiss the source so that the destination is ready, and finally remove the snapshot which you won't even notice because it will mirror the destination exactly.

Answer 2

If you want a simple trick ,try to set background color to window in AppDelegate's didFinishLaunchingWithOptions to your navigationbar's color, it works for me :) like this window?.backgroundColor = myColor