您是否知道为什么此self.navigationController.tabBarItem.badgeValue = @"1"无效?我遇到了同样的问题，但不知道为什么.
但这是这样的:

Did you figure out why this self.navigationController.tabBarItem.badgeValue = @"1" didn't work? I got the same problem but didn't know why.
But this way it works:

[[[[self tabBarController] tabBar] items] objectAtIndex:0] setBadgeValue:@"AB"];