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  • visibleViewController和topViewController 获取当前显示的页面

    原文:http://blog.sina.com.cn/s/blog_881ed8500102vo38.html

    UINavigationController 中有visibleViewController和topViewController

    今天通过一个demo了解了他们的异同

    visibleViewController 就是当前显示的控制器

    topViewController 是某个导航栈的栈顶视图

    visibleViewController和哪个导航栈没有关系,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,

    但是topViewController 就是某个导航栈的栈顶视图,和导航嘻嘻相关

    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。

    获取当前显示的控制器 UIWindow (Visible)

    - (UIViewController *)visibleViewController {
        UIViewController *rootViewController =[[[[UIApplicationsharedApplication] 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:[UITabBarControllerclass]]) {
            UITabBarController* tabBarController = (UITabBarController*)rootViewController;
            return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
        } else if ([rootViewController isKindOfClass:[UINavigationController class]]) {
            UINavigationController* navigationController = (UINavigationController*)rootViewController;
            return [self topViewControllerWithRootViewController:navigationController.visibleViewController];
        } else if (rootViewController.presentedViewController) {
            UIViewController* presentedViewController = rootViewController.presentedViewController;
            return [self topViewControllerWithRootViewController:presentedViewController];
        } else {
            return rootViewController;
        }
    }
    

      

    值得注意的是

    1、[[[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B

    A.presentedViewController=B

    B.presentingViewController=A

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  • 原文地址:https://www.cnblogs.com/qiyer/p/5364830.html
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