更改 AppDelegate 的根视图控制器导致 UIViewControllerHierarchyInconsistency 异常答案

【问题标题】：Change root view controller of AppDelegate cause an exception of UIViewControllerHierarchyInconsistency更改 AppDelegate 的根视图控制器导致 UIViewControllerHierarchyInconsistency 异常
【发布时间】：2019-03-06 08:21:45
【问题描述】：

在AppDelegate之外，我想更改它的rootViewController。换句话说，我想在我之前的窗口中放置一个新的导航控制器，然后在这个导航控制器中推送新的控制器：

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
    }
}

但是这个函数会导致应用程序崩溃并显示以下错误消息：

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

我该如何解决？

【问题讨论】：

标签： ios swift uiviewcontroller uinavigationcontroller appdelegate

【解决方案1】：

改变

let navigationController = UINavigationController(rootViewController: rootController)

到

let navigationController = UINavigationController(rootViewController: controller)

更新

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

【讨论】：

我希望将导航控制器放在我之前在窗口中的顶部，然后将新控制器推入其中，所以这个解决方案无法帮助它

【解决方案2】：

我没有尝试替换导航控制器，而是替换初始导航控制器中的根 VC，如下所示。

在 AppDelegate 中：

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
}

然后，我在 FirstViewController 中更改根 VC，如下所示：

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)
}

【讨论】：