ChangeRootViewController Swift

UIViewControllerExtension.swift

extension UIViewController {
  func changeRootViewController(to viewController: UIViewController, animated: Bool, completion: (() -> Void)?) {
    let toVC = viewController
    let snapshot = UIApplication.shared.keyWindow!.snapshotView(afterScreenUpdates: true)!
    
    let rootViewControllerChangeBlock = {
      toVC.view.addSubview(snapshot)
      UIApplication.shared.keyWindow?.rootViewController = toVC
      
      let duration = animated ? 0.3 : 0
      UIView.animate(withDuration: duration, animations: {
        snapshot.layer.opacity = 0
        snapshot.layer.transform = CATransform3DMakeScale(1.5, 1.5, 1.5)
      }, completion: { _ in
        snapshot.removeFromSuperview()
        completion?()
      })
    }
    
    if UIApplication.shared.keyWindow?.rootViewController?.presentedViewController != nil {
      UIApplication.shared.keyWindow?.addSubview(snapshot)
      UIApplication.shared.keyWindow?.rootViewController?.dismiss(animated: false, completion: {
        rootViewControllerChangeBlock()
      })
    } else {
      rootViewControllerChangeBlock()
    }
  }
}