自定义展开Segue期间导航栏为黑色

我做了一个习惯UIStoryboardSegue,但当它解开时,它似乎导致我UINavigationBar变黑,然后回到它的正确颜色.请参阅下面的GIF.

我的自定义segue只是让新的ViewController从顶部下来,然后返回到顶部.

这是UIStoryboardSegue代码:

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)
    })
}
}

如果我通过转到屏幕底部然后保持我的自定义来显示新视图,那么让我们放开它的默认设置,UINavigationBar保持它的正确颜色,只有当我使用我提供的代码来展开它UINavigationBar时动画期间黑色.

任何提示都将非常感激.

--- 编辑 ---

我玩了一下,如果我进入AppDelegate并UINavigationBar.appearance().isTranslucent = false改为true,我会得到一个白色的背景,但之后只是看起来导航栏突然出现了.我想知道是否出于某种原因被卸载然后在View Controller处于活动状态时重新加载.

--- 编辑2 ---

我有点能用黑客修复它.在我添加的AppDelegate内部func application(... didFinishLaunchingWithOptions ...),self.window?.backgroundColor = UIColor.{your color}但所有这一切都使得黑色部分现在显示为我的颜色,导航栏仍然在segue期间由于某种原因消失.