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

这是对Eric的回答的改进:

UIViewController *_topMostController(UIViewController *cont) {
    UIViewController *topController = cont;

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

    if ([topController isKindOfClass:[UINavigationController class]]) {
        UIViewController *visible = ((UINavigationController *)topController).visibleViewController;
        if (visible) {
            topController = visible;
        }
    }

    return (topController != cont ? topController : nil);
}

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

    UIViewController *next = nil;

    while ((next = _topMostController(topController)) != nil) {
        topController = next;
    }

    return topController;
}

UIViewController *cont是一个辅助函数。

现在你所需要做的就是调用topMostController()和最顶端的UIViewController应该被返回!

其他回答

简单的扩展UIApplication在Swift:

注意:

它关心UITabBarController中的moreNavigationController

extension UIApplication {

    class func topViewController(baseViewController: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {

        if let navigationController = baseViewController as? UINavigationController {
            return topViewController(navigationController.visibleViewController)
        }

        if let tabBarViewController = baseViewController as? UITabBarController {

            let moreNavigationController = tabBarViewController.moreNavigationController

            if let topViewController = moreNavigationController.topViewController where topViewController.view.window != nil {
                return topViewController(topViewController)
            } else if let selectedViewController = tabBarViewController.selectedViewController {
                return topViewController(selectedViewController)
            }
        }

        if let splitViewController = baseViewController as? UISplitViewController where splitViewController.viewControllers.count == 1 {
            return topViewController(splitViewController.viewControllers[0])
        }

        if let presentedViewController = baseViewController?.presentedViewController {
            return topViewController(presentedViewController)
        }

        return baseViewController
    }
}

简单的用法:

if let topViewController = UIApplication.topViewController() {
    //do sth with top view controller
}

你可以通过使用找到最顶层视图控制器

NSArray *arrViewControllers=[[self navigationController] viewControllers];
UIViewController *topMostViewController=(UIViewController *)[arrViewControllers objectAtIndex:[arrViewControllers count]-1];

伟大的解决方案在Swift,实现在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
}

不确定这是否会帮助你通过找到最顶层的视图控制器来实现,但我试图呈现一个新的视图控制器,但如果我的根视图控制器已经有一个模态对话框,它会被阻塞,所以我将循环到所有模态视图控制器的顶部使用以下代码:

UIViewController* parentController =[UIApplication sharedApplication].keyWindow.rootViewController;

while( parentController.presentedViewController &&
       parentController != parentController.presentedViewController )
{
    parentController = parentController.presentedViewController;
}

使用扩展为Swift获得最顶部的视图控制器

代码:

extension UIViewController {
    @objc func topMostViewController() -> UIViewController {
        // Handling Modal views
        if let presentedViewController = self.presentedViewController {
            return presentedViewController.topMostViewController()
        }
        // Handling UIViewController's added as subviews to some other views.
        else {
            for view in self.view.subviews
            {
                // Key property which most of us are unaware of / rarely use.
                if let subViewController = view.next {
                    if subViewController is UIViewController {
                        let viewController = subViewController as! UIViewController
                        return viewController.topMostViewController()
                    }
                }
            }
            return self
        }
    }
}

extension UITabBarController {
    override func topMostViewController() -> UIViewController {
        return self.selectedViewController!.topMostViewController()
    }
}

extension UINavigationController {
    override func topMostViewController() -> UIViewController {
        return self.visibleViewController!.topMostViewController()
    }
}

用法:

UIApplication.sharedApplication().keyWindow!.rootViewController!.topMostViewController()