Objectivec 嵌入自定义容器视图控制器时，内容位于导航栏下方.

UPDATE

根据Tim的回答，我在每个具有scrollview(或子类)的视图控制器中实现了以下内容，它是我的自定义容器的一部分:

- (void)didMoveToParentViewController:(UIViewController *)parent
{
    if (parent) {
        CGFloat top = parent.topLayoutGuide.length;
        CGFloat bottom = parent.bottomLayoutGuide.length;

        // this is the most important part here, because the first view controller added 
        // never had the layout issue, it was always the second. if we applied these
        // edge insets to the first view controller, then it would lay out incorrectly.
        // first detect if it's laid out correctly with the following condition, and if
        // not, manually make the adjustments since it seems like UIKit is failing to do so
        if (self.collectionView.contentInset.top != top) {
            UIEdgeInsets newInsets = UIEdgeInsetsMake(top, 0, bottom, 0);
            self.collectionView.contentInset = newInsets;
            self.collectionView.scrollIndicatorInsets = newInsets;
        }
    }

    [super didMoveToParentViewController:parent];
}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

我有一个名为SegmentedPageViewController的定制容器视图控制器.我把它设为UINavigationController's rootViewController.

SegmentedPageViewController的用途是允许设置为NavController标题视图的UISegmentedControl在不同的子视图控制器之间切换.

这些子视图控制器都包含scrollview、tableview或collection视图.

我们发现，第一个视图控制器加载良好，正确定位在导航栏下方.但是当我们换到一个新的

我们正在使用自动布局和界面生成器.我们已经想尽一切办法，但找不到一致的解决方案.

以下是主要代码块，用于设置第一个视图控制器，并在用户点击分段控件时切换到另一个视图控制器:

- (void)switchFromViewController:(UIViewController *)oldVC toViewController:(UIViewController *)newVC
{
    if (newVC == oldVC) return;

    // Check the newVC is non-nil otherwise expect a crash: NSInvalidArgumentException
    if (newVC) {

        // Set the new view controller frame (in this case to be the size of the available screen bounds)
        // Calulate any other frame animations here (e.g. for the oldVC)
        newVC.view.frame = self.view.bounds;

        // Check the oldVC is non-nil otherwise expect a crash: NSInvalidArgumentException
        if (oldVC) {
            // **** THIS RUNS WHEN A NEW VC IS SET ****
            // DIFFERENT FROM FIRST VC IN THAT WE TRANSITION INSTEAD OF JUST SETTING


            // Start both the view controller transitions
            [oldVC willMoveToParentViewController:nil];
            [self addChildViewController:newVC];

            // Swap the view controllers
            // No frame animations in this code but these would go in the animations block
            [self transitionFromViewController:oldVC
                              toViewController:newVC
                                      duration:0.25
                                       options:UIViewAnimationOptionLayoutSubviews
                                    animations:^{}
                                    completion:^(BOOL finished) {
                                        // Finish both the view controller transitions
                                        [oldVC removeFromParentViewController];
                                        [newVC didMoveToParentViewController:self];
                                        // Store a reference to the current controller
                                        self.currentViewController = newVC;
                                    }];
        } else {

            // **** THIS RUNS WHEN THE FIRST VC IS SET ****
            // JUST STANDARD VIEW CONTROLLER CONTAINMENT

            // Otherwise we are adding a view controller for the first time
            // Start the view controller transition
            [self addChildViewController:newVC];

            // Add the new view controller view to the view hierarchy
            [self.view addSubview:newVC.view];

            // End the view controller transition
            [newVC didMoveToParentViewController:self];

            // Store a reference to the current controller
            self.currentViewController = newVC;
        }
    }

}