在iOS 7中忽略了hidesBottomBarWhenPushed

此代码在iOS 7发布之前运行良好。我正在分配一个 UIViewController ，其中 hidesBottomBarWhenPushed 为 YES ，作为 UINavigationController 的 rootViewController 。但无论如何都会显示TabBar。以下是相关代码：

This code was working well until iOS 7 release. I'm assigning a UIViewController, with hidesBottomBarWhenPushed as YES, as the rootViewController of an UINavigationController. But the TabBar is being shown anyway. Here's the relevant code:

Login *lv = [[Login alloc] init];
lv.HowToUseShows = showHowToUse;
lv.hidesBottomBarWhenPushed = YES;

UINavigationController *BokShelfNav = [[UINavigationController alloc] initWithRootViewController:lv];

//... 

UITabBarController *tbController = [[UITabBarController alloc] init];
tbController.viewControllers = @[BokShelfNav,...];

任何有类似问题的人？