Question

据我所知，这可以在Objective-C中使用：

self.window.rootViewController.class == myViewController

如何检查当前视图控制器是否是特定的视图控制器？

Answer 1

要检查Swift中的类，请使用"is" (as explained under "checking Type" in the chapter called Type Casting in the Swift Programming Guide)

if self.window.rootViewController is MyViewController {
    //do something if it's an instance of that class
}

Answer 2

针对swift3编译器进行了更新，使其更加贴合！和？

if let wd = UIApplication.shared.delegate?.window {
        var vc = wd!.rootViewController
        if(vc is UINavigationController){
            vc = (vc as! UINavigationController).visibleViewController

        }

        if(vc is LogInViewController){
            //your code
        }
    }

Answer 3

如果使用导航控制器，则可以轻松迭代视图控制器。然后您可以检查特定实例：

if let viewControllers = navigationController?.viewControllers {
    for viewController in viewControllers {
        // some process
        if viewController.isKindOfClass(MenuViewController) {
            println("yes it is")
        }
    } 
}

Answer 4

我必须在AppDelegate中找到当前的viewController。我用过这个

//at top of class
var window:UIWindow?

// inside my method/function
if let viewControllers = window?.rootViewController?.childViewControllers {
    for viewController in viewControllers {
        if viewController.isKindOfClass(MyViewControllerClass) {
            println("Found it!!!")
            }
        }
    }

Answer 5

试试这个

if self is MyViewController {        

}

Answer 6

要想了解Thapa的答案，你需要在使用之前转换到viewcontroller类......

   if let wd = self.view.window {
        var vc = wd.rootViewController!
        if(vc is UINavigationController){
            vc = (vc as! UINavigationController).visibleViewController
        }
        if(vc is customViewController){
            var viewController : customViewController = vc as! customViewController

Answer 7

Swift 3

不确定你们，但我很难用这个。我做了这样的事情：

if let window = UIApplication.shared.delegate?.window {
    if var viewController = window?.rootViewController {
        // handle navigation controllers
        if(viewController is UINavigationController){
            viewController = (viewController as! UINavigationController).visibleViewController!
        }
        print(viewController)
    }
}

我一直在获取应用的初始视图控制器。出于某种原因，它想要保留根视图控制器，无论如何。所以我只创建了一个全局字符串类型变量currentViewController并在每个viewDidLoad()中自己设置它的值。我只需要知道我在哪个屏幕上＆amp;这对我很有用。

Answer 8

Swift 4，Swift 5

req.Header["User-Agent"]

Answer 9

对于类型，您可以使用is，如果它是您自己的viewcontroller类，那么您需要使用isKindOfClass，如：

let vcOnTop = self.embeddedNav.viewControllers[self.embeddedNav.viewControllers.count-1]
            if vcOnTop.isKindOfClass(VcShowDirections){
                return
            }

Answer 10

斯威夫特3 |检查视图控制器是否是其自身的根。

您可以在视图控制器中访问window，只需使用self.view.window。

上下文：我需要更新视图的位置并在旋转设备时触发动画。如果视图控制器处于活动状态，我只想这样做。

class MyViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(
            self, 
            selector: #selector(deviceDidRotate), 
            name: .UIApplicationDidChangeStatusBarOrientation, 
            object: nil
        )
    }

    func deviceDidRotate() {
        guard let window = self.view.window else { return }

        // check if self is root view controller
        if window.rootViewController == self {
            print("vc is self")
        }

        // check if root view controller is instance of MyViewController
        if window.rootViewController is MyViewController {
            print("vc is MyViewController")
        }
    }
}

如果在MyViewController处于活动状态时旋转设备，您将看到上面的行打印到控制台。如果MyViewController未激活，您将看不到它们。

如果您对我使用UIDeviceOrientationDidChange代替.UIDeviceOrientationDidChange的原因感到好奇，请查看this answer。

Answer 11

  SELECT *
  FROM ORGANIZATION_TABLE
  START WITH PARENT_ID       = 6
  CONNECT BY PRIOR   CHILD_ID = PARENT_ID;

Answer 12

检查对我来说更有效的方法What is .self

if ((self.window.rootViewController?.isKind(of: WebViewController.self))!)
{
  //code
}

Answer 13

if let index = self.navigationController?.viewControllers.index(where: { $0 is MyViewController }) {
            let vc = self.navigationController?.viewControllers[vcIndex] as! MyViewController
            self.navigationController?.popToViewController(vc, animated: true)
        } else {
            self.navigationController?.popToRootViewController(animated: true)
        }

Answer 14

 var top = window?.rootViewController
            while ((top?.presentedViewController) != nil) {
                top = top?.presentedViewController
            }
            
            if !(type(of: top!) === CallingVC.self) {
                top?.performSegue(withIdentifier: "CallingVC", sender: call)
            }

你如何检查Swift中的当前视图控制器类？

14 个答案: