Helpful method to dismiss ALL view controllers presented on top of a root view/navigation controller.

gistfile1.m

/**
    Helpful method to dismiss ALL view controllers presented on top of a 
    root view/navigation controller.
    
    This method is useful if you have a variable number of view controllers
    that you'd need to dimiss to return to a base view. Used for my purposes 
    from the AppDelegate class during the process of handling the opening of
    a URL scheme.
    
    This method also relies on implementing a category on UIViewController 
    (or whatever your base view controller subclass is) to find the current
    topmost view controller. These methods are included at the bottom of 
    this gist.
    
    Usage:
        [self dismissAllModalAndCoveringViewControllers]
    
*/
- (NSInteger)findRootViewController:(UIViewController *)viewController
{
    if (viewController) {
        return 1 + [self findRootViewController:viewController.presentingViewController];
    }
    return 0;
}

- (void)dismissAllModalAndCoveringViewControllers
{
    UIViewController *currentViewController = [UIViewController currentViewController];

    NSInteger numVCToDismiss = [self findRootViewController:currentViewController];
    if (numVCToDismiss > 1) {
        [currentViewController dismissViewControllerAnimated:YES completion:^{
            [self dismissAllSignInAndTourViewControllers];
        }];
    }
}

/////////////////////////////////////////////////////////////////////////////////////

/**
    Implement these methods in a category on UIViewController
    
    These methods taken from this post on Stack Overflow:
    http://stackoverflow.com/questions/24825123/get-the-current-view-controller-from-the-app-delegate
*/

+ (UIViewController *)findBestViewController:(UIViewController *)vc
{    
    if (vc.presentedViewController) {
        
        // Return presented view controller
        return [UIViewController findBestViewController:vc.presentedViewController];
        
    } else if ([vc isKindOfClass:[UISplitViewController class]]) {
        
        // Return right hand side
        UISplitViewController* svc = (UISplitViewController*) vc;
        if (svc.viewControllers.count > 0)
            return [UIViewController findBestViewController:svc.viewControllers.lastObject];
        else
            return vc;
        
    } else if ([vc isKindOfClass:[UINavigationController class]]) {
        
        // Return top view
        UINavigationController* svc = (UINavigationController*) vc;
        if (svc.viewControllers.count > 0)
            return [UIViewController findBestViewController:svc.topViewController];
        else
            return vc;
        
    } else if ([vc isKindOfClass:[UITabBarController class]]) {
        
        // Return visible view
        UITabBarController* svc = (UITabBarController*) vc;
        if (svc.viewControllers.count > 0)
            return [UIViewController findBestViewController:svc.selectedViewController];
        else
            return vc;
        
    } else {
        
        // Unknown view controller type, return last child view controller
        return vc;
        
    }
    
}

+ (UIViewController *)currentViewController
{
    UIViewController *viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
    return [UIViewController findBestViewController:viewController];
}