我需要一个根视图控制器的实例.
I need an instance of root view controller.
我尝试了这些方法:
UIViewController *rootViewController = (UIViewController*)[[[UIApplication sharedApplication] keyWindow] rootViewController];
返回:null:
当我尝试获取控制器数组时:
Also when I try to get an array of controllers:
NSArray *viewControllers = self.navigationController.viewControllers;
它只返回一个控制器,但它不是我的根视图控制器.
It returns only one controller, but it isn't my root view controller.
如果我尝试从导航控制器中获取:
If I try to take from navigation controller:
UIViewController *root = (UIViewController*)[self.navigationController.viewControllers objectAtIndex:0];
返回:null:
任何想法为什么?我还能尝试获取根视图控制器的实例吗?
Any ideas why? What else could I try to get an instance of my root view controller?
谢谢.
如果您尝试访问您在 appDelegate 中设置的 rootViewController
.试试这个:
if you are trying to access the rootViewController
you set in your appDelegate. try this:
Objective-C
YourViewController *rootController = (YourViewController*)[[(YourAppDelegate*)
[[UIApplication sharedApplication]delegate] window] rootViewController];
斯威夫特
let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
let viewController = appDelegate.window!.rootViewController as YourViewController
斯威夫特 3
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let viewController = appDelegate.window!.rootViewController as! YourViewController
斯威夫特 4 &4.2
let viewController = UIApplication.shared.keyWindow!.rootViewController as! YourViewController
斯威夫特 5 &5.1 &5.2
let viewController = UIApplication.shared.windows.first!.rootViewController as! YourViewController
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