iPhone — How to find topmost view controller

Question

I've run into a couple of cases now where it would be convenient to be able to find the "topmost" view controller (the one responsible for the current view), but haven't found a way to do it.

Basically the challenge is this: Given that one is executing in a class that is not a view controller (or a view) [and does not have the address of an active view] and has not been passed the address of the topmost view controller (or, say, the address of the navigation controller), is it possible to find that view controller? (And, if so, how?)

Or, failing that, is it possible to find the topmost view?

Answer 1

To complete JonasG's answer (who left out tab bar controllers while traversing), here is my version of returning the currently visible view controller:

- (UIViewController*)topViewController {
    return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}

- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController {
    if ([rootViewController isKindOfClass:[UITabBarController class]]) {
        UITabBarController* tabBarController = (UITabBarController*)rootViewController;
        return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
    } else if ([rootViewController isKindOfClass:[UINavigationController class]]) {
        UINavigationController* navigationController = (UINavigationController*)rootViewController;
        return [self topViewControllerWithRootViewController:navigationController.visibleViewController];
    } else if (rootViewController.presentedViewController) {
        UIViewController* presentedViewController = rootViewController.presentedViewController;
        return [self topViewControllerWithRootViewController:presentedViewController];
    } else {
        return rootViewController;
    }
}

Answer 2

And another Swift solution

extension UIViewController {
    static var topmostViewController: UIViewController? {
        return UIApplication.sharedApplication().keyWindow?.topmostViewController
    }

    var topmostViewController: UIViewController? {
        return presentedViewController?.topmostViewController ?? self
    }
}

extension UINavigationController {
    override var topmostViewController: UIViewController? {
        return visibleViewController?.topmostViewController
    }
}

extension UITabBarController {
    override var topmostViewController: UIViewController? {
        return selectedViewController?.topmostViewController
    }
}

extension UIWindow {
    var topmostViewController: UIViewController? {
        return rootViewController?.topmostViewController
    }
}

Answer 3

This answer includes childViewControllers and maintains a clean and readable implementation.

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

    return [rootViewController topVisibleViewController];
}

- (UIViewController *)topVisibleViewController
{
    if ([self isKindOfClass:[UITabBarController class]])
    {
        UITabBarController *tabBarController = (UITabBarController *)self;
        return [tabBarController.selectedViewController topVisibleViewController];
    }
    else if ([self isKindOfClass:[UINavigationController class]])
    {
        UINavigationController *navigationController = (UINavigationController *)self;
        return [navigationController.visibleViewController topVisibleViewController];
    }
    else if (self.presentedViewController)
    {
        return [self.presentedViewController topVisibleViewController];
    }
    else if (self.childViewControllers.count > 0)
    {
        return [self.childViewControllers.lastObject topVisibleViewController];
    }

    return self;
}

Answer 4

Great solution in Swift, implement in AppDelegate

func getTopViewController()->UIViewController{
    return topViewControllerWithRootViewController(UIApplication.sharedApplication().keyWindow!.rootViewController!)
}
func topViewControllerWithRootViewController(rootViewController:UIViewController)->UIViewController{
    if rootViewController is UITabBarController{
        let tabBarController = rootViewController as! UITabBarController
        return topViewControllerWithRootViewController(tabBarController.selectedViewController!)
    }
    if rootViewController is UINavigationController{
        let navBarController = rootViewController as! UINavigationController
        return topViewControllerWithRootViewController(navBarController.visibleViewController)
    }
    if let presentedViewController = rootViewController.presentedViewController {
        return topViewControllerWithRootViewController(presentedViewController)
    }
    return rootViewController
}

Answer 5

Here is my take on this. Thanks to @Stakenborg for pointing out the way to skip getting UIAlertView as the top most controller

-(UIWindow *) returnWindowWithWindowLevelNormal
{
    NSArray *windows = [UIApplication sharedApplication].windows;
    for(UIWindow *topWindow in windows)
    {
        if (topWindow.windowLevel == UIWindowLevelNormal)
            return topWindow;
    }
    return [UIApplication sharedApplication].keyWindow;
}

-(UIViewController *) getTopMostController
{
    UIWindow *topWindow = [UIApplication sharedApplication].keyWindow;
    if (topWindow.windowLevel != UIWindowLevelNormal)
    {
        topWindow = [self returnWindowWithWindowLevelNormal];
    }

    UIViewController *topController = topWindow.rootViewController;
    if(topController == nil)
    {
        topWindow = [UIApplication sharedApplication].delegate.window;
        if (topWindow.windowLevel != UIWindowLevelNormal)
        {
            topWindow = [self returnWindowWithWindowLevelNormal];
        }
        topController = topWindow.rootViewController;
    }

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

    if([topController isKindOfClass:[UINavigationController class]])
    {
        UINavigationController *nav = (UINavigationController*)topController;
        topController = [nav.viewControllers lastObject];

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

    return topController;
}

Answer 6

A lot of these answers are incomplete. Although this is in Objective-C, this is the best compilation of all of them that I could put together for right now, as a non-recursive block:

... Link to gist, in case it gets revised: https://gist.github.com/benguild/0d149bb3caaabea2dac3d2dca58c0816

... Code for reference/comparison:

UIViewController *(^topmostViewControllerForFrontmostNormalLevelWindowBlock)(void)=^UIViewController * // NOTE: Adapted from various stray answers here: https://stackoverflow.com/questions/6131205/iphone-how-to-find-topmost-view-controller/20515681
{
    __block UIViewController *viewController;

    [[[[[UIApplication sharedApplication] windows] reverseObjectEnumerator] allObjects] enumerateObjectsUsingBlock:^(__kindof UIWindow * _Nonnull window, NSUInteger idx, BOOL * _Nonnull stop)
    {
        if ([window windowLevel]==UIWindowLevelNormal)
        {
            viewController=[window rootViewController];
            ////

            *stop=YES;

        }

    } ];

    while (viewController)
    {
        if ([viewController isKindOfClass:[UITabBarController class]])
        {
            viewController=[(UITabBarController *)viewController selectedViewController];

        }
        else if ([viewController isKindOfClass:[UINavigationController class]])
        {
            viewController=[(UINavigationController *)viewController visibleViewController];

        }
        else if ([viewController presentedViewController] && ![[viewController presentedViewController] isBeingDismissed])
        {
            viewController=[viewController presentedViewController];

        }
        else if ([[viewController childViewControllers] count]>0)
        {
            viewController=[[viewController childViewControllers] lastObject];

        }
        else
        {
            __block BOOL needsRepeat=NO;

            [[[[[viewController view] subviews] reverseObjectEnumerator] allObjects] enumerateObjectsUsingBlock:^(__kindof UIView * _Nonnull view, NSUInteger idx, BOOL * _Nonnull stop)
            {
                if ([[view nextResponder] isKindOfClass:[UIViewController class]])
                {
                    viewController=(UIViewController *)[view nextResponder];

                    needsRepeat=YES;
                    ////

                    *stop=YES;

                }

            } ];

            if (!needsRepeat)
            {
                break;

            }

        }

    }

    return viewController;

};