ios 如何从 AppDelegate 上的 TabBarController 获取 ViewController？
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How can I get ViewController from TabBarController on AppDelegate?
提问by Ariel Zehao Zhang
I use iOS5 storyboard, and my initial view controller is TabBarController, there are four relationships to view1 & view2 & view3 & view4, so, how can I get the view3's view controller?
我使用iOS5 storyboard，我的初始视图控制器是TabBarController，view1&view2&view3&view4有四个关系，那么，我怎样才能得到view3的视图控制器？
I tried:
我试过：
[[[[self.window.rootViewController navigationController] tabBarController] viewControllers] objectAtIndex:2];
But it doesn't work...
但它不起作用...
回答by Dima
You said that your initial (root) view controller is a UITabBarController but you are referring to a view controller with a navigation controller with a tab bar controller. Are you getting mixed up in your view controller hierarchy?
你说你的初始（根）视图控制器是一个 UITabBarController 但你指的是一个带有导航控制器和标签栏控制器的视图控制器。您是否在视图控制器层次结构中混淆了？
edit:
编辑：
if your root view controller is actually just a tab bar controller and you want to get the 3rd tab here is the code:
如果您的根视图控制器实际上只是一个标签栏控制器，并且您想获得第三个标签，则代码如下：
[[((UITabBarController *)self.window.rootViewController) viewControllers] objectAtIndex:2];
回答by Haider
[self.tabBarController setSelectedIndex:2];
回答by Tunvir Rahman Tusher
Try this way
试试这个方法
In any view controller
在任何视图控制器中
YourViewController *yourViewController= (YourViewController*) [self.tabBarController.viewControllers objectAtIndex:3];
this return your that view controller object.Cast it to your view controller and you are ready to use that. run and Go
这将返回您的视图控制器对象。将它投射到您的视图控制器，您就可以使用它了。跑去
回答by vilas
UIViewController *loginViewController=self.window.rootViewController;
UITabBarController *controller=loginViewController.tabBarControllerObj;
UIViewController *selectedController=controller.selectedViewController;
From this you will get selected view controller.
从中您将获得选定的视图控制器。
For getting all view controller just replace
要获取所有视图控制器，只需替换
NSArray *viewControllers = [controller viewControllers];
回答by Gurjinder Singh
Swift 4.0
斯威夫特 4.0
let viewC = self?.tabBarController.viewControllers.first // will give single Navigation Controller on index 0
let viewC = self?.tabBarController?.viewControllers// will give array of Navigation Controller
Further you can check the Visible ViewController
此外，您可以检查 Visible ViewController
if let nav = viewC as? UINavigationController {
if nav.visibleViewController is YourViewControllerName{
// Do Code
}
}
