在AppDelegate.m的屏幕上获取当前显示的UIViewController

屏幕上的当前UIViewController需要响应来自APN的推送通知，通过设置一些徽章视图。 但是我怎么能得到方法application:didReceiveRemoteNotification的UIViewController application:didReceiveRemoteNotification ：的AppDelegate.m ？

我尝试使用self.window.rootViewController获取当前显示的UIViewController ，它可能是一个UINavigationViewController或其他types的视图控制器。 我发现UINavigationViewController的visibleViewController属性可以用来获取屏幕上的UIViewController 。 但是，如果不是UINavigationViewController我该怎么办？

任何帮助表示赞赏！ 相关的代码如下。

AppDelegate.m

 ... - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo { //I would like to find out which view controller is on the screen here. UIViewController *vc = [(UINavigationViewController *)self.window.rootViewController visibleViewController]; [vc performSelector:@selector(handleThePushNotification:) withObject:userInfo]; } ... 

ViewControllerA.m

 - (void)handleThePushNotification:(NSDictionary *)userInfo{ //set some badge view here } 

Answer 1

当你的控制器不是UINavigationController时，你也可以使用rootViewController ：

 UIViewController *vc = self.window.rootViewController; 

一旦你知道了根视图控制器，那么这取决于你如何构build你的UI，但你可能find一种方法来浏览控制器层次结构。

如果您提供关于您定义应用的方式的更多详细信息，那么我可能会提供更多的提示。

编辑：

如果你想要最顶层的视图 （不是视图控制器），你可以检查

 [[[[UIApplication sharedApplication] keyWindow] subviews] lastObject]; 

尽pipe这种观点可能是隐形的，甚至可以被某些子视图所覆盖。

再次，这取决于你的用户界面，但这可能有帮助…

Answer 2

我总是喜欢涉及类别的解决scheme，因为它们是可以重复使用的。

所以我在UIWindow上创build了一个类。 你现在可以在UIWindow上调用visibleViewController，这将通过search控制器层次结构来获得可见的视图控制器。 如果您正在使用导航和/或标签栏控制器，这将起作用。 如果你有其他types的控制器build议，请让我知道，我可以添加它。

UIWindow + PazLabs.h（头文件）

 #import <UIKit/UIKit.h> @interface UIWindow (PazLabs) - (UIViewController *) visibleViewController; @end 

UIWindow + PazLabs.m（实现文件）

 #import "UIWindow+PazLabs.h" @implementation UIWindow (PazLabs) - (UIViewController *)visibleViewController { UIViewController *rootViewController = self.rootViewController; return [UIWindow getVisibleViewControllerFrom:rootViewController]; } + (UIViewController *) getVisibleViewControllerFrom:(UIViewController *) vc { if ([vc isKindOfClass:[UINavigationController class]]) { return [UIWindow getVisibleViewControllerFrom:[((UINavigationController *) vc) visibleViewController]]; } else if ([vc isKindOfClass:[UITabBarController class]]) { return [UIWindow getVisibleViewControllerFrom:[((UITabBarController *) vc) selectedViewController]]; } else { if (vc.presentedViewController) { return [UIWindow getVisibleViewControllerFrom:vc.presentedViewController]; } else { return vc; } } } @end 

Swift版本

 public extension UIWindow { public var visibleViewController: UIViewController? { return UIWindow.getVisibleViewControllerFrom(self.rootViewController) } public static func getVisibleViewControllerFrom(_ vc: UIViewController?) -> UIViewController? { if let nc = vc as? UINavigationController { return UIWindow.getVisibleViewControllerFrom(nc.visibleViewController) } else if let tc = vc as? UITabBarController { return UIWindow.getVisibleViewControllerFrom(tc.selectedViewController) } else { if let pvc = vc?.presentedViewController { return UIWindow.getVisibleViewControllerFrom(pvc) } else { return vc } } } } 

Answer 3

您也可以通过NSNotificationCenter发布通知。 这让我们来处理遍历视图控制器层次结构的许多情况，例如当模态被呈现时等等。

例如，

 // MyAppDelegate.h NSString * const UIApplicationDidReceiveRemoteNotification; // MyAppDelegate.m NSString * const UIApplicationDidReceiveRemoteNotification = @"UIApplicationDidReceiveRemoteNotification"; - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo { [[NSNotificationCenter defaultCenter] postNotificationName:UIApplicationDidReceiveRemoteNotification object:self userInfo:userInfo]; } 

在每个视图控制器中：

 -(void)viewDidLoad { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didReceiveRemoteNotification:) name:UIApplicationDidReceiveRemoteNotification object:nil]; } -(void)viewDidUnload { [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidReceiveRemoteNotification object:nil]; } -(void)didReceiveRemoteNotification:(NSDictionary *)userInfo { // see http://stackoverflow.com/a/2777460/305149 if (self.isViewLoaded && self.view.window) { // handle the notification } } 

您也可以将这种方法用于仪器控制，当收到通知时需要更新，并由多个视图控制器使用。 在这种情况下，分别在init和dealloc方法中处理添加/删除观察者调用。

Answer 4

UIApplication在Swift中的简单扩展（甚至关心iPhone上的UITabBarController moreNavigationController） ：

 extension UIApplication { class func topViewController(base: UIViewController? = UIApplication.sharedApplication().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 where top.view.window != nil { return topViewController(top) } else if let selected = tab.selectedViewController { return topViewController(selected) } } if let presented = base?.presentedViewController { return topViewController(base: presented) } return base } } 

简单的用法：

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

完美的作品:-)

Answer 5

我发现iOS 8已经搞砸了。 在iOS 7中，只要有模态地呈现的UINavigationController就在视图层次结构上有一个新的UITransitionView 。 无论如何，这是我的代码find最顶级的VC。 调用getTopMostViewController应该返回一个VC，你应该能够发送一个消息，如presentViewController:animated:completion 。 它的目的是让你一个VC，你可以用它来呈现一个模态的VC，所以它很可能会停止并返回像UINavigationController这样的容器类而不是它们中包含的VC。 也不应该很难适应代码来做到这一点。 我已经在iOS 6,7和8的各种情况下testing了这个代码。请让我知道，如果你发现错误。

 + (UIViewController*) getTopMostViewController { UIWindow *window = [[UIApplication sharedApplication] keyWindow]; if (window.windowLevel != UIWindowLevelNormal) { NSArray *windows = [[UIApplication sharedApplication] windows]; for(window in windows) { if (window.windowLevel == UIWindowLevelNormal) { break; } } } for (UIView *subView in [window subviews]) { UIResponder *responder = [subView nextResponder]; //added this block of code for iOS 8 which puts a UITransitionView in between the UIWindow and the UILayoutContainerView if ([responder isEqual:window]) { //this is a UITransitionView if ([[subView subviews] count]) { UIView *subSubView = [subView subviews][0]; //this should be the UILayoutContainerView responder = [subSubView nextResponder]; } } if([responder isKindOfClass:[UIViewController class]]) { return [self topViewController: (UIViewController *) responder]; } } return nil; } + (UIViewController *) topViewController: (UIViewController *) controller { BOOL isPresenting = NO; do { // this path is called only on iOS 6+, so -presentedViewController is fine here. UIViewController *presented = [controller presentedViewController]; isPresenting = presented != nil; if(presented != nil) { controller = presented; } } while (isPresenting); return controller; } 

Answer 6

less于所有其他解决scheme的代码：

Objective-C版本：

 - (UIViewController *)getTopViewController { UIViewController *topViewController = [[[[UIApplication sharedApplication] delegate] window] rootViewController]; while (topViewController.presentedViewController) topViewController = topViewController.presentedViewController; return topViewController; } 

Swift 2.0版本:(信贷史蒂夫.B）

 func getTopViewController() -> UIViewController { var topViewController = UIApplication.sharedApplication().delegate!.window!!.rootViewController! while (topViewController.presentedViewController != nil) { topViewController = topViewController.presentedViewController! } return topViewController } 

即使使用模式，也可以在应用中的任何位置使用。

Answer 7

码

下面是在Swift 3中使用伟大的开关语法的一种方法：

 extension UIWindow { /// Returns the currently visible view controller if any reachable within the window. public var visibleViewController: UIViewController? { return UIWindow.visibleViewController(from: rootViewController) } /// Recursively follows navigation controllers, tab bar controllers and modal presented view controllers starting /// from the given view controller to find the currently visible view controller. /// /// - Parameters: /// - viewController: The view controller to start the recursive search from. /// - Returns: The view controller that is most probably visible on screen right now. public static func visibleViewController(from viewController: UIViewController?) -> UIViewController? { switch viewController { case let navigationController as UINavigationController: return UIWindow.visibleViewController(from: navigationController.visibleViewController ?? navigationController.topViewController) case let tabBarController as UITabBarController: return UIWindow.visibleViewController(from: tabBarController.selectedViewController) case let presentingViewController where viewController?.presentedViewController != nil: return UIWindow.visibleViewController(from: presentingViewController?.presentedViewController) default: return viewController } } } 

基本的想法和zirinisp的答案是一样的，只是使用了一个更像Swift 3的语法。

---

用法

您可能需要创build一个名为UIWindowExtension.swift的文件。 确保它包含import UIKit语句，现在复制上面的扩展代码 。

在呼叫方，它可以使用没有任何特定的视图控制器 ：

 if let visibleViewCtrl = UIApplication.shared.keyWindow?.visibleViewController { // do whatever you want with your `visibleViewCtrl` } 

或者，如果你知道你可见的视图控制器可以从特定的视图控制器访问 ：

 if let visibleViewCtrl = UIWindow.visibleViewController(from: specificViewCtrl) { // do whatever you want with your `visibleViewCtrl` } 

我希望它有帮助！

Answer 8

为每个ViewController指定标题，然后按照下面的代码获取当前ViewController的标题。

 -(void)viewDidUnload { NSString *currentController = self.navigationController.visibleViewController.title; 

然后按照你的标题来检查

  if([currentController isEqualToString:@"myViewControllerTitle"]){ //write your code according to View controller. } } 

Answer 9

zirinisp的答案Swift：

 extension UIWindow { func visibleViewController() -> UIViewController? { if let rootViewController: UIViewController = self.rootViewController { return UIWindow.getVisibleViewControllerFrom(rootViewController) } return nil } class func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController { if vc.isKindOfClass(UINavigationController.self) { let navigationController = vc as UINavigationController return UIWindow.getVisibleViewControllerFrom( navigationController.visibleViewController) } else if vc.isKindOfClass(UITabBarController.self) { let tabBarController = vc as UITabBarController return UIWindow.getVisibleViewControllerFrom(tabBarController.selectedViewController!) } else { if let presentedViewController = vc.presentedViewController { return UIWindow.getVisibleViewControllerFrom(presentedViewController.presentedViewController!) } else { return vc; } } } } 

用法：

  if let topController = window.visibleViewController() { println(topController) } 

Answer 10

为什么不在应用程序委托中处理推送通知代码？ 它是否与视图直接相关？

你可以通过检查视图的window属性是否有值来检查当前UIViewController的视图是否可见。 在这里看到更多。

Answer 11

关于NSNotificationCenter上面的post（抱歉找不到在哪里发表评论…）

万一有人得到 – [NSConcreteNotification allKeys]错误的种类。 改变这个：

 -(void)didReceiveRemoteNotification:(NSDictionary *)userInfo 

对此：

 -(void)didReceiveRemoteNotification:(NSNotification*)notif { NSDictionary *dict = notif.userInfo; } 

Answer 12

除了@zirinisp答案。

创build一个文件，将其命名为UIWindowExtension.swift并粘贴下面的代码片段：

 import UIKit public extension UIWindow { public var visibleViewController: UIViewController? { return UIWindow.getVisibleViewControllerFrom(self.rootViewController) } public static func getVisibleViewControllerFrom(vc: UIViewController?) -> UIViewController? { if let nc = vc as? UINavigationController { return UIWindow.getVisibleViewControllerFrom(nc.visibleViewController) } else if let tc = vc as? UITabBarController { return UIWindow.getVisibleViewControllerFrom(tc.selectedViewController) } else { if let pvc = vc?.presentedViewController { return UIWindow.getVisibleViewControllerFrom(pvc) } else { return vc } } } } func getTopViewController() -> UIViewController? { let appDelegate = UIApplication.sharedApplication().delegate if let window = appDelegate!.window { return window?.visibleViewController } return nil } 

使用它在任何地方：

 if let topVC = getTopViewController() { } 

感谢@zirinisp。

Answer 13

这对我有效。 我有很多目标有不同的控制器，所以以前的答案似乎没有工作。

首先你需要在你的AppDelegate类中：

 var window: UIWindow? 

然后，在你的function

 let navigationController = window?.rootViewController as? UINavigationController if let activeController = navigationController!.visibleViewController { if activeController.isKindOfClass( MyViewController ) { println("I have found my controller!") } } 

Answer 14

Swift 2.0版本的jungledev的答案

 func getTopViewController() -> UIViewController { var topViewController = UIApplication.sharedApplication().delegate!.window!!.rootViewController! while (topViewController.presentedViewController != nil) { topViewController = topViewController.presentedViewController! } return topViewController } 

Answer 15

这是我尝试过的最好的方法。 如果它应该帮助任何人…

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

Answer 16

 extension UIApplication { /// The top most view controller static var topMostViewController: UIViewController? { return UIApplication.shared.keyWindow?.rootViewController?.visibleViewController } } extension UIViewController { /// The visible view controller from a given view controller var visibleViewController: UIViewController? { if let navigationController = self as? UINavigationController { return navigationController.topViewController?.visibleViewController } else if let tabBarController = self as? UITabBarController { return tabBarController.selectedViewController?.visibleViewController } else if let presentedViewController = presentedViewController { return presentedViewController.visibleViewController } else { return self } } } 

有了这个，你可以像这样轻松地获得顶部的视图控制器

 let viewController = UIApplication.topMostViewController 

有一件事要注意的是，如果有一个UIAlertController目前正在显示， UIApplication.topMostViewController将返回一个UIAlertController 。

Answer 17

我使用visibleViewControllers属性为UIApplication创build了一个类别。 主要想法很简单。 我在UIViewController viewDidDisappear viewDidAppear和viewDidDisappear方法。 在viewDidAppear方法中，viewController被添加到堆栈中。 在viewDidDisappear方法中，viewController从堆栈中移除。 NSPointerArray来代替NSArray来存储弱UIViewController的引用。 这种方法适用于任何viewControllers层次结构。

UIApplication的+ VisibleViewControllers.h

 #import <UIKit/UIKit.h> @interface UIApplication (VisibleViewControllers) @property (nonatomic, readonly) NSArray<__kindof UIViewController *> *visibleViewControllers; @end 

UIApplication的+ VisibleViewControllers.m

 #import "UIApplication+VisibleViewControllers.h" #import <objc/runtime.h> @interface UIApplication () @property (nonatomic, readonly) NSPointerArray *visibleViewControllersPointers; @end @implementation UIApplication (VisibleViewControllers) - (NSArray<__kindof UIViewController *> *)visibleViewControllers { return self.visibleViewControllersPointers.allObjects; } - (NSPointerArray *)visibleViewControllersPointers { NSPointerArray *pointers = objc_getAssociatedObject(self, @selector(visibleViewControllersPointers)); if (!pointers) { pointers = [NSPointerArray weakObjectsPointerArray]; objc_setAssociatedObject(self, @selector(visibleViewControllersPointers), pointers, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } return pointers; } @end @implementation UIViewController (UIApplication_VisibleViewControllers) + (void)swizzleMethodWithOriginalSelector:(SEL)originalSelector swizzledSelector:(SEL)swizzledSelector { Method originalMethod = class_getInstanceMethod(self, originalSelector); Method swizzledMethod = class_getInstanceMethod(self, swizzledSelector); BOOL didAddMethod = class_addMethod(self, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod)); if (didAddMethod) { class_replaceMethod(self, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod)); } else { method_exchangeImplementations(originalMethod, swizzledMethod); } } + (void)load { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ [self swizzleMethodWithOriginalSelector:@selector(viewDidAppear:) swizzledSelector:@selector(uiapplication_visibleviewcontrollers_viewDidAppear:)]; [self swizzleMethodWithOriginalSelector:@selector(viewDidDisappear:) swizzledSelector:@selector(uiapplication_visibleviewcontrollers_viewDidDisappear:)]; }); } - (void)uiapplication_visibleviewcontrollers_viewDidAppear:(BOOL)animated { [[UIApplication sharedApplication].visibleViewControllersPointers addPointer:(__bridge void * _Nullable)self]; [self uiapplication_visibleviewcontrollers_viewDidAppear:animated]; } - (void)uiapplication_visibleviewcontrollers_viewDidDisappear:(BOOL)animated { NSPointerArray *pointers = [UIApplication sharedApplication].visibleViewControllersPointers; for (int i = 0; i < pointers.count; i++) { UIViewController *viewController = [pointers pointerAtIndex:i]; if ([viewController isEqual:self]) { [pointers removePointerAtIndex:i]; break; } } [self uiapplication_visibleviewcontrollers_viewDidDisappear:animated]; } @end 

https://gist.github.com/medvedzzz/e6287b99011f2437ac0beb5a72a897f0

Swift 3版本

UIApplication的+ VisibleViewControllers.swift

 import UIKit extension UIApplication { private struct AssociatedObjectsKeys { static var visibleViewControllersPointers = "UIApplication_visibleViewControllersPointers" } fileprivate var visibleViewControllersPointers: NSPointerArray { var pointers = objc_getAssociatedObject(self, &AssociatedObjectsKeys.visibleViewControllersPointers) as! NSPointerArray? if (pointers == nil) { pointers = NSPointerArray.weakObjects() objc_setAssociatedObject(self, &AssociatedObjectsKeys.visibleViewControllersPointers, pointers, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC) } return pointers! } var visibleViewControllers: [UIViewController] { return visibleViewControllersPointers.allObjects as! [UIViewController] } } extension UIViewController { private static func swizzleFunc(withOriginalSelector originalSelector: Selector, swizzledSelector: Selector) { let originalMethod = class_getInstanceMethod(self, originalSelector) let swizzledMethod = class_getInstanceMethod(self, swizzledSelector) let didAddMethod = class_addMethod(self, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod)) if didAddMethod { class_replaceMethod(self, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod)) } else { method_exchangeImplementations(originalMethod, swizzledMethod); } } override open class func initialize() { if self != UIViewController.self { return } let swizzlingClosure: () = { UIViewController.swizzleFunc(withOriginalSelector: #selector(UIViewController.viewDidAppear(_:)), swizzledSelector: #selector(uiapplication_visibleviewcontrollers_viewDidAppear(_:))) UIViewController.swizzleFunc(withOriginalSelector: #selector(UIViewController.viewDidDisappear(_:)), swizzledSelector: #selector(uiapplication_visibleviewcontrollers_viewDidDisappear(_:))) }() swizzlingClosure } @objc private func uiapplication_visibleviewcontrollers_viewDidAppear(_ animated: Bool) { UIApplication.shared.visibleViewControllersPointers.addPointer(Unmanaged.passUnretained(self).toOpaque()) uiapplication_visibleviewcontrollers_viewDidAppear(animated) } @objc private func uiapplication_visibleviewcontrollers_viewDidDisappear(_ animated: Bool) { let pointers = UIApplication.shared.visibleViewControllersPointers for i in 0..<pointers.count { if let pointer = pointers.pointer(at: i) { let viewController = Unmanaged<AnyObject>.fromOpaque(pointer).takeUnretainedValue() as? UIViewController if viewController.isEqual(self) { pointers.removePointer(at: i) break } } } uiapplication_visibleviewcontrollers_viewDidDisappear(animated) } } 

https://gist.github.com/medvedzzz/ee6f4071639d987793977dba04e11399

Answer 18

我的更好！ 🙂

 extension UIApplication { var visibleViewController : UIViewController? { return keyWindow?.rootViewController?.topViewController } } extension UIViewController { fileprivate var topViewController: UIViewController { switch self { case is UINavigationController: return (self as! UINavigationController).visibleViewController?.topViewController ?? self case is UITabBarController: return (self as! UITabBarController).selectedViewController?.topViewController ?? self default: return presentedViewController?.topViewController ?? self } } }