UINavigationController 中有visibleViewController和topViewController
visibleViewController
当前显示的控制器topViewController
是某个导航栈的栈顶视图visibleViewController
跟导航栈没有关系,只是当前显示的控制器,也就是说任意一个导航的visibleViewController
所返回的值应该是一样的,- topViewController 是某个导航栈的栈顶视图,和导航控制器相关
换句话说如果在仅有一个导航栈上,visibleViewController
和topViewController
应该是没有区别得。
方法一 : 获取当前显示的控制器 UIWindow (Visible)
- (UIViewController *)visibleViewController { UIViewController *rootViewController =[[[[UIApplication sharedApplication] delegate] window] 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; } } }
方法二 :
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController { if ([rootViewController isKindOfClass:[UITabBarController class]]) { UITabBarController* tabBarController = (UITabBarController*)rootViewController; return [self topViewControllerWithRootViewController:tabBarController.selectedViewController]; } else if (rootViewController.presentedViewController) { UIViewController* presentedViewController = rootViewController.presentedViewController; return [self topViewControllerWithRootViewController:presentedViewController]; } else if ([rootViewController isKindOfClass:[UINavigationController class]]) { UINavigationController* navigationController = (UINavigationController*)rootViewController; return [self topViewControllerWithRootViewController:navigationController.visibleViewController]; } else { return rootViewController; } }
值得注意的是
[[[UIApplication sharedApplication] keyWindow] rootViewController]
有时为nil 比如当页面有菊花在转的时候,这个rootViewController就为nil;所以使用
[[[[UIApplication sharedApplication] delegate] window] rootViewController]
或者[[[[UIApplication sharedApplication] windows] objectAtIndex:0] rootViewController]
presentedViewController
和presentingViewController
当A弹出BA.presentedViewController=B
B.presentingViewController=A