更改AppDelegate的根视图控制器会导致UIViewControllerHierarchyInconsistency异常

Question

Outside the AppDelegate , I want to change the rootViewController of it. In other words, I want to put a new navigation controller on top of what I had before in my window and then push the new controller in this navigation controller:

func JumpToPage(_ controller: UIViewController) {
        guard let rootController = AppDelegate.shared?.presentationViewController else {
            return
        }
        let navigationController = UINavigationController(rootViewController: rootController)
        navigationController.pushViewController(controller, animated: true)
        AppDelegate.shared?.window?.rootViewController = navigationController
    }
}

But this function cause the app to crash with the following error message:

Terminating app due to uncaught exception 'UIViewControllerHierarchyInconsistency',
    reason: 'adding a root view controller <MyExampleController> as a child of view controller:<UINavigationController>'

How should I solve it?

Answer 1

Change from

let navigationController = UINavigationController(rootViewController: rootController)

To

let navigationController = UINavigationController(rootViewController: controller)

Update

func JumpToPage(_ controller: UIViewController) {
    guard let rootController = AppDelegate.shared?.presentationViewController else {
        return
    }
    let navigationController = UINavigationController(rootViewController: controller)
    AppDelegate.shared?.window?.rootViewController = navigationController
}

Answer 2

Instead of trying to replace navigation controller, I'm replacing root VC in the initial navigation controller as follows.

In AppDelegate:

func application(_ application: UIApplication, didFinishLaunchingWithOptions ...) {
    let storyboard = UIStoryboard(name: "FirstVC", bundle: Bundle.main)
    let firstViewController = instantiateInitialViewController()! as! FirstViewController
    navigationController = UINavigationController(rootViewController: firstViewController)
    window = UIWindow(frame: UIScreen.main.bounds)
    window!.rootViewController = navigationController
    window!.makeKeyAndVisible()
    return true
}

Then, I change root VC w/in FirstViewController as follows:

func someFuncInFirstVC() {
    let allControllers = NSMutableArray(array: self.navigationController!.viewControllers)
    allControllers.removeObject(at: allControllers.count - 1)  // remove root VC, count should be one...
    let secondViewController = SecondViewController()
    allControllers.add(secondViewController as AnyObject)  // this becomes new root VC since nav stack is empty now
    navigationController!.setViewControllers(allControllers as [AnyObject] as! [UIViewController], animated: true)
}