#swtws

ChangeRoot.swift

guard let window = UIApplication.sharedApplication().appDelegate.window, rootViewController = window.rootViewController else { return }
let newRootViewController = UINavigationController(rootViewController: vc)

// rootViewControllerを差し替える場合は、メモリリーク防止のため事前にdismissを行います
// https://gist.github.com/mono0926/abd7d079361f36efdd9068b27b41ea50
UIView.transitionWithView(window, duration: 0.2, options: .CurveEaseInOut, animations: {
    rootViewController.dismissdismissViewControllerAnimated(false, completion: nil)
    window.rootViewController = newRootViewController
}) { _ in }

// rootViewControllerを差し替えず、ChildViewControllerの差し替えで行う方法もあります
// refs. http://dealforest.hatenablog.com/entry/2016/12/14/124555
UIView.transitionWithView(window, duration: 0.2, options: .CurveEaseInOut, animations: {
    rootViewController.childViewControllers.forEach {
      $0.view.removeFromSuperview()
      $0.removeFromParentViewController()
    }
    rootViewController.view.addSubView(newRootViewController.view)
    rootViewController.addChildViewController(newRootViewController)
    newRootViewController.didMoveToParentViewController(rootViewController)
}) { _ in }