来自 AppDelegate 的当前视图控制器？

Question

有没有办法从 AppDelegate 获取当前视图控制器？我知道有 rootViewController，但这不是我要找的。

Answer 1

如果您的应用程序的根视图控制器是 UINavigationController，您可以这样做：

((UINavigationController*)appDelegate.window.rootViewController).visibleViewController;

同样，如果它是 UITabBarController，您可以这样做：

((UITabBarController*)appDelegate.window.rootViewController).selectedViewController;

当然，像这样的显式转换是肮脏的。更好的方法是使用强类型自己捕获引用。

Answer 2

这可能对

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

- (UIViewController *)topViewController:(UIViewController *)rootViewController
{
  if (rootViewController.presentedViewController == nil) {
    return rootViewController;
  }

  if ([rootViewController.presentedViewController isKindOfClass:[UINavigationController class]]) {
    UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
    UIViewController *lastViewController = [[navigationController viewControllers] lastObject];
    return [self topViewController:lastViewController];
  }

  UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;
  return [self topViewController:presentedViewController];
}

Swift 版本有帮助：

extension UIApplication {
    class func topViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
        if let nav = base as? UINavigationController {
            return topViewController(base: nav.visibleViewController)
        }
        if let tab = base as? UITabBarController {
            if let selected = tab.selectedViewController {
                return topViewController(base: selected)
            }
        }
        if let presented = base?.presentedViewController {
            return topViewController(base: presented)
        }
        return base
    }
}

取自：
https://gist.github.com/snikch/3661188

Answer 3

如果您将 UINavigationController 放入 appDelegate 中，则使用其属性 topViewController 或 visibleViewController

Answer 4

进行扩展：

extension UIApplication {
    class func topViewController(base: UIViewController? = UIApplication.sharedApplication().keyWindow?.rootViewController) -> UIViewController? {
        if let nav = base as? UINavigationController {
            return topViewController(nav.visibleViewController)
        }
        if let tab = base as? UITabBarController {
            let moreNavigationController = tab.moreNavigationController

            if let top = moreNavigationController.topViewController where top.view.window != nil {
                return topViewController(top)
            } else if let selected = tab.selectedViewController {
                return topViewController(selected)
            }
        }
        if let presented = base?.presentedViewController {
            return topViewController(presented)
        }
        return base
    }
}

用法：

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

Answer 5

获取 appDelegate 对象：

MyAppDelegate *tmpDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];

正如 beryllium 建议的那样，您可以使用 UINavigationController 的属性来访问当前的视图控制器。

所以代码看起来像：

id myCurrentController = tmpDelegate.myNavigationController.topViewController;

或：

NSArray *myCurrentViewControllers = tmpDelegate.myNavigationController.viewControllers;

Answer 6

您可以通过查找它的presentedViewController从rootViewController获取当前视图控制器，如下所示：

UIViewController *parentViewController = [[[UIApplication sharedApplication] delegate] window].rootViewController;

while (parentViewController.presentedViewController != nil){
    parentViewController = parentViewController.presentedViewController;
}
UIViewController *currentViewController = parentViewController;

它与我一起工作。希望它有帮助:)

Answer 7

对于任何不使用UINavigationController但其默认视图控制器是UIViewController的人，您可以使用以下命令检查哪个视图控制器处于活动状态（或呈现） 正如您所看到的，

func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> Int {
    if let rootViewController = self.window!.rootViewController {
        if let presentedViewController = rootViewController.presentedViewController {
            return presentedViewController.supportedInterfaceOrientations()
        }
    } // Else current view controller is DefaultViewController

    return Int(UIInterfaceOrientationMask.Portrait.rawValue)
}

我正在检查当前视图控制器，以便支持特定视图控制器的不同界面方向。对于任何有兴趣使用此方法来支持特定方向的人，应将以下内容放置在需要特定方向的每个视图控制器中。

override func supportedInterfaceOrientations() -> Int {
    return Int(UIInterfaceOrientationMask.All.rawValue)
} 

注意：此代码是使用 Swift 1.2 编写的

Answer 8

UIApplication 扩展采用 Swift 4+ 语法，基于 AG 的解决方案

public extension UIApplication {

    class func topViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
        if let nav = base as? UINavigationController {
            return topViewController(base: nav.visibleViewController)
        }
        if let tab = base as? UITabBarController {
            let moreNavigationController = tab.moreNavigationController

            if let top = moreNavigationController.topViewController, top.view.window != nil {
                return topViewController(base: top)
            } else if let selected = tab.selectedViewController {
                return topViewController(base: selected)
            }
        }
        if let presented = base?.presentedViewController {
            return topViewController(base: presented)
        }
        return base
    }
}

示例用法：

if let rootViewController = UIApplication.topViewController() {
     //do something with rootViewController
}

Answer 9

快速解决方案：

 self.window.rootViewController.presentedViewController. 

这应该可以满足您的需求。

Answer 10

我经常需要检索当前显示的视图控制器。它可能意味着当前 UINavigationController 堆栈顶部的视图控制器、当前呈现的视图控制器等。所以我编写了这个函数，它在大多数情况下都能解决这个问题，并且您可以在 UIViewController 扩展中使用它。

Swift 3 中的代码：

func currentViewController(
_ viewController: UIViewController? =
    UIApplication.shared.keyWindow?.rootViewController)
        -> UIViewController? {
    guard let viewController =
    viewController else { return nil }

    if let viewController =
        viewController as? UINavigationController {
        if let viewController =
            viewController.visibleViewController {
            return currentViewController(viewController)
        } else {
            return currentViewController(
                viewController.topViewController)
        }
    } else if let viewController =
            viewController as? UITabBarController {
        if let viewControllers =
            viewController.viewControllers,
            viewControllers.count > 5,
            viewController.selectedIndex >= 4 {
            return currentViewController(
                viewController.moreNavigationController)
        } else {
            return currentViewController(
                viewController.selectedViewController)
        }
    } else if let viewController =
            viewController.presentedViewController {
        return viewController
    } else if viewController.childViewControllers.count > 0 {
        return viewController.childViewControllers[0]
    } else {
        return viewController
    }
}

使用以下方式调用：currentViewController()

Answer 11

如果有人想要 Objective C。

GlobalManager.h

//
//  GlobalManager.h
//  Communicator
//
//  Created by Mushrankhan Pathan on 21/10/21.
//  Copyright © 2021 Ribbideo. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface GlobalManager : NSObject

typedef void (^ ActionBlock)(void);

+(UIViewController*)currentController;
+(UIViewController*)currentController:(UIViewController*) baseController;

@end

NS_ASSUME_NONNULL_END

GlobalManager.m

//
//  GlobalManager.m
//  Communicator
//
//  Created by Mushrankhan Pathan on 21/10/21.
//  Copyright © 2021 Ribbideo. All rights reserved.
//

#import "GlobalManager.h"

@implementation GlobalManager

+(UIViewController*)currentController
{
    UIViewController *base = UIApplication.sharedApplication.keyWindow.rootViewController;
    return [GlobalManager currentController:base];
}

+(UIViewController*)currentController:(UIViewController*) baseController
{
    if ([baseController isKindOfClass:[UINavigationController class]]) {
        return [GlobalManager currentController:((UINavigationController*)baseController).visibleViewController];
    }
    
    if ([baseController isKindOfClass:[UITabBarController class]]) {
        UINavigationController* moreNavigationController = ((UITabBarController*)baseController).moreNavigationController;
        UIViewController* top = moreNavigationController.topViewController;
        if (top.view.window != nil) {
            return [GlobalManager currentController:top];
        }
        UIViewController* selectedViewController = ((UITabBarController*)baseController).selectedViewController;
        if (selectedViewController != nil) {
            return [GlobalManager currentController:selectedViewController];
        }
    }
    
    if (baseController.presentedViewController != nil) {
        return [GlobalManager currentController:baseController.presentedViewController];
    }
    
    return baseController;
}

@end

如何使用。

UIViewController *currentVC = [GlobalManager currentController];