从应用程序委托获取当前视图控制器

Question

我是iOS的新手。我需要从应用程序委托中知道当前的视图控制器。我对此一无所知，也不知道如何实现。我正在使用以下代码来实现这个功能，但它返回空值。我遵循了这个链接-从应用程序委托获取当前视图控制器（模态可行）。需要帮助。

- user3459648

---

你是否正在使用导航控制器？否则，请发布您的代码以更好地理解。 - Retro

Answer 1

以下是我用来查找用户最可能正在交互的当前视图控制器的方法：

UIViewController+Utils.h

#import <UIKit/UIKit.h>

@interface UIViewController (Utils)

+(UIViewController*) currentViewController;

@end

UIViewController+Utils.m

#import "UIViewController+Utils.h"

@implementation UIViewController (Utils)

+(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 {

    // Find best view controller
    UIViewController* viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
    return [UIViewController findBestViewController:viewController];

}

@end

那么，每当我需要来自应用程序中任何位置的当前视图控制器时，只需使用：

[UIViewController currentViewController]

- jjv360

Answer 2

以下是一些我放在实用类中的Swift类/静态函数，可以帮助您：

// Returns the most recently presented UIViewController (visible)
class func getCurrentViewController() -> UIViewController? {

    // If the root view is a navigation controller, we can just return the visible ViewController
    if let navigationController = getNavigationController() {

        return navigationController.visibleViewController
    }

    // Otherwise, we must get the root UIViewController and iterate through presented views
    if let rootController = UIApplication.shared.keyWindow?.rootViewController {

        var currentController: UIViewController! = rootController

        // Each ViewController keeps track of the view it has presented, so we
        // can move from the head to the tail, which will always be the current view
        while( currentController.presentedViewController != nil ) {

            currentController = currentController.presentedViewController
        }
        return currentController
    }
    return nil
}

// Returns the navigation controller if it exists
class func getNavigationController() -> UINavigationController? {

    if let navigationController = UIApplication.shared.keyWindow?.rootViewController  {

        return navigationController as? UINavigationController
    }
    return nil
}

- Alexander Miller

---

我成功地使用了这个，但需要进行修改才能编译。需要进行一些重新排列。 - Harold Ship

@alaxandermiller，我该如何使用这些来获取视图控制器名称作为字符串？ - Famic Tech

Answer 3

这是jjv360的优秀答案的Swift版本， （我去掉了一些冗余的换行符，认为Swift更易读）

func getCurrentViewController(_ vc: UIViewController) -> UIViewController? {
    if let pvc = vc.presentedViewController {
        return getCurrentViewController(pvc)
    }
    else if let svc = vc as? UISplitViewController, svc.viewControllers.count > 0 {
        return getCurrentViewController(svc.viewControllers.last!)
    }
    else if let nc = vc as? UINavigationController, nc.viewControllers.count > 0 {
        return getCurrentViewController(nc.topViewController!)
    }
    else if let tbc = vc as? UITabBarController {
        if let svc = tbc.selectedViewController {
            return getCurrentViewController(svc)
        }
    }
    return vc
}

从您的AppDelegate开始，

    guard let rvc = self.window?.rootViewController else {
        return
    }
    if let vc = getCurrentViewController(rvc) {
        // do your stuff here
    }

- endavid

Answer 4

这帮助我找到了可见的视图控制器。我搜索了现有的方法，但没有找到任何方法。所以我编写了自己的定制方法。

-(id)getCurrentViewController
{
    id WindowRootVC = [[[[UIApplication sharedApplication] delegate] window] rootViewController];

    id currentViewController = [self findTopViewController:WindowRootVC];

    return currentViewController;
}

-(id)findTopViewController:(id)inController
{
    /* if ur using any Customs classes, do like this.
     * Here SlideNavigationController is a subclass of UINavigationController.
     * And ensure you check the custom classes before native controllers , if u have any in your hierarchy.
    if ([inController isKindOfClass:[SlideNavigationController class]])
    {
        return [self findTopViewController:[inController visibleViewController]];
    }
    else */
    if ([inController isKindOfClass:[UITabBarController class]])
    {
        return [self findTopViewController:[inController selectedViewController]];
    }
    else if ([inController isKindOfClass:[UINavigationController class]])
    {
        return [self findTopViewController:[inController visibleViewController]];
    }
    else if ([inController isKindOfClass:[UIViewController class]])
    {
        return inController;
    }
    else
    {
        NSLog(@"Unhandled ViewController class : %@",inController);
        return nil;
    }
}

示例用法：

-(void)someMethod
{
    id currentVC = [self getCurrentViewController];
        if (currentVC)
        {
            NSLog(@"currentVC :%@",currentVC);
        }
}

- Abdusha M A

Answer 5

这取决于您如何设置用户界面。如果您的用户界面是按照这种方式设置的，您可能会获得您的rootViewController并浏览整个层次结构。

UIViewController *vc = self.window.rootViewController;

- thomasdclark

---

我可以通过以下方式获取视图控制器名称 - 上一个视图控制器是vc == <ViewController：0x8d52290>，但我想要视图控制器的名称。 - user3459648

如果你正在关注这个问题并且想要控制器的名称，请尝试使用id vc = self.window.rootViewController; NSLog(@"Controller Name : %@", [vc class]); - Abdusha M A

Answer 6

UIViewController* actualVC = [anyViewController.navigationController.viewControllers lastObject];

- Reconquistador

Answer 7

我获取了根视图控制器，然后遍历展示的视图控制器：

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

while (current.presentedViewController) {
    current = current.presentedViewController;
}
//now you can use current, for example to present an alert view controller:
[current presentViewController:alert animated:YES completion:nil];

- Jorge Arimany

Answer 8

Swift解决方案 对于iOS 13+，我们有SceneDelegate 和多个窗口，因此您需要使用以下代码：

private func getCurrentViewController() -> UIViewController? {
    if let rootViewController = UIApplication.shared.windows.first?.rootViewController {
        
        if let presentedViewController = rootViewController.presentedViewController {
            return presentedViewController
        }
        
        return rootViewController
    }
    
    return nil
} 

- Wissa

Answer 9

这是我尝试过的最佳解决方案。

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

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

    return topController;
}

- Mayur Deshmukh

Answer 10

|*| 从导航视图控制器获取可见视图控制器

let NavVccVar = UIApplication.sharedApplication().keyWindow?.rootViewController as! UINavigationController
let ShnSrnVar = NavVccVar.visibleViewController

---

|*| 从可见视图控制器中呈现

let NavVccVar = UIApplication.sharedApplication().keyWindow?.rootViewController as! UINavigationController
NavVccVar.visibleViewController!.presentViewController(NamVccVar, animated: true, completion: nil)

- Sujay U N