我遇到了一些情况,现在,它将是方便的,能够找到“最顶层”的视图控制器(一个负责当前视图),但还没有找到一种方法。

基本上,挑战是这样的:给定一个在一个类中执行,这个类不是一个视图控制器(或一个视图)[并且没有活动视图的地址],并且没有传递最顶层视图控制器的地址(或者,比如说,导航控制器的地址),是否有可能找到那个视图控制器?(如果是的话,是怎么做到的?)

或者,如果找不到,有没有可能找到最高处的风景?


当前回答

我认为Rajesh的解决方案几乎是完美的,但我认为从上到下遍历子视图更好,我改为如下:

+ (UIViewController *)topViewController:(UIViewController *)viewController{

    if (viewController.presentedViewController)
    {

            UIViewController *presentedViewController = viewController.presentedViewController;
            return [self topViewController:presentedViewController];
     } 
     else if ([viewController isKindOfClass:[UITabBarController class]])
     {

            UITabBarController *tabBarController = (UITabBarController *)viewController;
            return [self topViewController:tabBarController.selectedViewController];
    }

         else if ([viewController isKindOfClass:[UINavigationController class]])
    {   

            UINavigationController *navController = (UINavigationController *)viewController;

            return [self topViewController:navController.visibleViewController];
    }

    // Handling UIViewController's added as subviews to some other views.
    else {

        NSInteger subCount = [viewController.view subviews].count - 1;

        for (NSInteger index = subCount; index >=0 ; --index)
        {

            UIView *view = [[viewController.view subviews] objectAtIndex:index];

            id subViewController = [view nextResponder];    // Key property which most of us are unaware of / rarely use.

            if ( subViewController && [subViewController isKindOfClass:[UIViewController class]])
            {
                return [self topViewController:subViewController];
            }
        }
        return viewController;
    }
}

其他回答

之前的答案似乎不能处理rootController是UITabBarController或UINavigationController的情况。

下面是swift中适用于这些情况的函数:

func getCurrentView() -> UIViewController?
{
    if let window = UIApplication.sharedApplication().keyWindow, var currentView: UIViewController = window.rootViewController
    {
        while (currentView.presentedViewController != nil)
        {
            if let presented = currentView.presentedViewController
            {
                currentView = presented
            }
        }

        if currentView is UITabBarController
        {
            if let visible = (currentView as! UITabBarController).selectedViewController
            {
                currentView = visible;
            }
        }

        if currentView is UINavigationController
        {
            if let visible = (currentView as! UINavigationController).visibleViewController
            {
                currentView = visible;
            }
        }

        return currentView
    }

    return nil
}

斯威夫特5

试试这个

let topVisibleVC = UIApplication.shared.keyWindow?.rootViewController?.visibleViewController

我认为你需要一个公认的答案和@fishstix的组合

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

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

    return topController;
}

Swift 3.0 +

func topMostController() -> UIViewController? {
    guard let window = UIApplication.shared.keyWindow, let rootViewController = window.rootViewController else {
        return nil
    }

    var topController = rootViewController

    while let newTopController = topController.presentedViewController {
        topController = newTopController
    }

    return topController
}

我的问题有点不同,我在我的应用程序中使用SWRevealViewController。 我使用了Yuchen Zhong的答案,但它总是返回topViewController作为SWRevealViewController。对于那些使用SWRevealViewController或其他一些pod来开发侧菜单的人。以下是我对钟宇晨回答的延伸:

extension UIApplication {
class func topViewController() -> UIViewController? {
    var topVC = shared.keyWindow!.rootViewController
    while true {
        if let presented = topVC?.presentedViewController {
            topVC = presented
        } else if let nav = topVC as? UINavigationController {
            topVC = nav.visibleViewController
        } else if let tab = topVC as? UITabBarController {
            topVC = tab.selectedViewController
        }else if let swRVC = topVC as? SWRevealViewController {
            topVC = swRVC.frontViewController
        } else {
            break
        }
    }
    return topVC
}
}

iOS 4在UIWindow上引入了rootViewController属性:

[UIApplication sharedApplication].keyWindow.rootViewController;

你需要在创建视图控制器后自己设置。