ChangeRoot.swift

ChangeRoot.swift

extension UIWindow {
  
  /// Fix for http://stackoverflow.com/a/27153956/849645
  func set(rootViewController newRootViewController: UIViewController,
           withTransition transition: CATransition? = nil) {
    
    let previousViewController = rootViewController
    
    if let transition = transition {
      // Add the transition
      layer.add(transition, forKey: kCATransition)
    }
    
    rootViewController = newRootViewController
    
    // Update status bar appearance using the new view controllers appearance - animate if needed
    if UIView.areAnimationsEnabled {
      UIView.animate(withDuration: CATransaction.animationDuration()) {
        newRootViewController.setNeedsStatusBarAppearanceUpdate()
      }
    } else {
      newRootViewController.setNeedsStatusBarAppearanceUpdate()
    }
    
    if #available(iOS 13.0, *) {
      // In iOS 13 we don't want to remove the transition view as it'll create a blank screen
    } else {
      // The presenting view controllers view doesn't get removed from the window as its currently transistioning and presenting a view controller
      if let transitionViewClass = NSClassFromString("UITransitionView") {
        for subview in subviews where subview.isKind(of: transitionViewClass) {
          subview.removeFromSuperview()
        }
      }
    }
    if let previousViewController = previousViewController {
      // Allow the view controller to be deallocated
      previousViewController.dismiss(animated: false) {
        // Remove the root view in case its still showing
        previousViewController.view.removeFromSuperview()
      }
    }
  }
}