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警告：尝试在视图不在窗口层次结构中显示* on * - swift

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如果数据模型中有任何已保存的数据，我正在尝试显示 ViewController . 但是我收到以下错误：

警告：尝试显示其视图不在窗口层次结构中的* on *

相关代码：

override func viewDidLoad() {
    super.viewDidLoad()
    loginButton.backgroundColor = UIColor.orangeColor()

    var request = NSFetchRequest(entityName: "UserData")
    request.returnsObjectsAsFaults = false

    var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
    var context:NSManagedObjectContext = appDel.managedObjectContext!

    var results:NSArray = context.executeFetchRequest(request, error: nil)!

    if(results.count <= 0){
        print("Inga resultat")
    } else {
        print("SWITCH VIEW PLOX")
        let internVC = self.storyboard?.instantiateViewControllerWithIdentifier("internVC") as internViewController
        self.presentViewController(internVC, animated: true, completion: nil)
    }
}

我尝试过使用谷歌找到的不同解决方案但没有成功 .

ios swift hierarchy presentviewcontroller

12 回答

  • 32

    在目标c：当在mpmovieplayer上呈现viewcontroller时，这解决了我的问题

    - (UIViewController*) topMostController
{
    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;

    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }

    return topController;
}
    回复于
  • 0

    此时，在代码中，视图控制器的视图仅已创建，但未添加到任何视图层次结构中 . 如果你想尽快从那个视图控制器出现，你应该在 viewDidAppear 中做到最安全 .

    回复于
  • 0

    斯威夫特3

    我有这个不断出现作为一个新手，并发现当前加载模态视图，可以被解雇，但切换到根控制器是最好的，如果你不需要显示模态 .

    我正在使用它

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc  = storyboard?.instantiateViewController(withIdentifier: "MainAppStoryboard") as! TabbarController
present(vc, animated: false, completion: nil)

    使用它来代替我的tabController：

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
let view = storyboard.instantiateViewController(withIdentifier: "MainAppStoryboard") as UIViewController
let appDelegate = UIApplication.shared.delegate as! AppDelegate
//show window
appDelegate.window?.rootViewController = view

    如果您需要在多个故事板屏幕之间切换，只需调整到视图控制器即可 .

    回复于
  • 2

    你只需要执行一个延迟选择器 - （0秒工作） .

    override func viewDidLoad() {
    super.viewDidLoad()
    perform(#selector(presentExampleController), with: nil, afterDelay: 0)
}

@objc private func presentExampleController() {
    let exampleStoryboard = UIStoryboard(named: "example", bundle: nil)
    let exampleVC = storyboard.instantiateViewController(withIdentifier: "ExampleVC") as! ExampleVC
    present(exampleVC, animated: true) 
}
    回复于
  • 28

    斯威夫特3 .

    调用此函数以获取最顶层的视图控制器，然后使该视图控制器存在 .

    func topMostController() -> UIViewController {
    var topController: UIViewController = UIApplication.shared.keyWindow!.rootViewController!
        while (topController.presentedViewController != nil) {
            topController = topController.presentedViewController!
        }
        return topController
    }

    用法：

    let topVC = topMostController()
let vcToPresent = self.storyboard!.instantiateViewController(withIdentifier: "YourVCStoryboardID") as! YourViewController
topVC.present(vcToPresent, animated: true, completion: nil)
    回复于
  • 1

    对于SWIFT

    func topMostController() -> UIViewController {
    var topController: UIViewController = UIApplication.sharedApplication().keyWindow!.rootViewController!
    while (topController.presentedViewController != nil) {
        topController = topController.presentedViewController!
    }
    return topController
}
    回复于
  • 3

    斯威夫特4

    func topMostController() -> UIViewController {
    var topController: UIViewController = UIApplication.shared.keyWindow!.rootViewController!
    while (topController.presentedViewController != nil) {
        topController = topController.presentedViewController!
    }
    return topController
}
    回复于
  • 1

    对于swift 3.0及以上版本

    public static func getTopViewController() -> UIViewController?{
if var topController = UIApplication.shared.keyWindow?.rootViewController
{
  while (topController.presentedViewController != nil)
  {
    topController = topController.presentedViewController!
  }
  return topController
}
return nil}
    回复于
  • 10
    let storyboard = UIStoryboard(name: "test", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "teststoryboard") as UIViewController
UIApplication.shared.keyWindow?.rootViewController?.present(vc, animated: true, completion: nil)

    这似乎有助于确保它是最顶级的观点 .

    我收到了一个错误

    警告：尝试在myapp.testController上显示myapp.testController：0x7fdd01703990：0x7fdd01703690，其视图不在窗口层次结构中！

    希望这有助于其他人迅速3

    回复于
  • 13

    我试过这么多approches！唯一有用的是：

    if var topController = UIApplication.shared.keyWindow?.rootViewController
{
  while (topController.presentedViewController != nil)
  {
    topController = topController.presentedViewController!
  }
}
    回复于
  • 110

    当你有 UINavigationController 或 UITabBarController 时，topViewController的所有实现都不是完全支持的情况，对于那两个你需要稍微不同的处理：

    对于 UITabBarController 和 UINavigationController ，您需要一个不同的实现 .

    这是我用来获取topMostViewController的代码：

    protocol TopUIViewController {
    func topUIViewController() -> UIViewController?
}

extension UIWindow : TopUIViewController {
    func topUIViewController() -> UIViewController? {
        if let rootViewController = self.rootViewController {
            return self.recursiveTopUIViewController(from: rootViewController)
        }

        return nil
    }

    private func recursiveTopUIViewController(from: UIViewController?) -> UIViewController? {
        if let topVC = from?.topUIViewController() { return recursiveTopUIViewController(from: topVC) ?? from }
        return from
    }
}

extension UIViewController : TopUIViewController {
    @objc open func topUIViewController() -> UIViewController? {
        return self.presentedViewController
    }
}

extension UINavigationController {
    override open func topUIViewController() -> UIViewController? {
        return self.visibleViewController
    }
}

extension UITabBarController {
    override open func topUIViewController() -> UIViewController? {
        return self.selectedViewController ?? presentedViewController
    }
}
    回复于
  • 12

    可以使用，而不是找到顶视图控制器

    viewController.modalPresentationStyle = UIModalPresentationStyle.currentContext

    其中viewController是你想要呈现的控制器当像TabBar，NavBar这样的层次结构中存在不同类型的视图时这很有用，尽管其他视图似乎是正确的但更多的是hackish

    其他演示风格可在apple doc找到

    回复于

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