UITabBar子视图更改顺序

我正在迭代UITabBar视图，如下所示：

for (UIView *view in [tabBar subviews]) { if ([view isKindOfClass:[UIControl class]]) { tabBarItemFrame = [tabBar convertRect:view.frame toView:self.view]; } } 

订单最初是：

 <_UITabBarBackgroundView: 0x7a62e150; frame = (0 0; 768 49); autoresize = W; userInteractionEnabled = NO; layer = >, <GSBadgeView: 0x7b1b6060; frame = (0 0; 0 0); hidden = YES; layer = >, <UITabBarButton: 0x7d75ee80; frame = (71 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7d75ef90; frame = (181 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7d75f180; frame = (291 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7d75f6f0; frame = (401 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7b026060; frame = (511 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7b002960; frame = (621 1; 76 48); opaque = NO; layer = >, <UIImageView: 0x7a62fdf0; frame = (0 -1; 768 1); autoresize = W; userInteractionEnabled = NO; layer = > 

退出应用程序并返回后，订单将更改为：

 <_UITabBarBackgroundView: 0x7a62e150; frame = (0 0; 768 49); autoresize = W; userInteractionEnabled = NO; layer = >, <GSBadgeView: 0x7b1b6060; frame = (0 0; 0 0); hidden = YES; layer = >, <UITabBarButton: 0x7d75ef90; frame = (181 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7d75f180; frame = (291 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7d75f6f0; frame = (401 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7b026060; frame = (511 1; 76 48); opaque = NO; layer = >, <UITabBarButton: 0x7b002960; frame = (621 1; 76 48); opaque = NO; layer = >, <UIImageView: 0x7a62fdf0; frame = (0 -1; 768 1); autoresize = W; userInteractionEnabled = NO; layer = >, <UITabBarButton: 0x7d75ee70; frame = (71 1; 76 48); opaque = NO; layer = > 

差不多，第一个标签栏按钮位于subviews数组的末尾。 视觉上布局是正确的，我没有做任何事来操纵子视图。

任何人都可以提供任何见解吗？ 我不应该依赖子视图来维护特定的订单吗？

更新

正如@rmaddy在下面提到的那样，挖掘子视图是不必要的。 我使用下面的代码获得了适当的框架：

 NSInteger helpBarButtonIndex = [self.viewControllers indexOfObject:self.helpMenuVC]; UIView *helpBarButton = [[[self.tabBar items] objectAtIndex:helpBarButtonIndex] view]; tabBarItemFrame = [self.tabBar convertRect:helpBarButton.frame toView:self.view];