UIScrollView only shows part of UIView after rotation

First of all, you don't need to recreate all the constraints in the -updateViewConstraints method. You just need to update them at this location. To achieve your goal, do the following:

• Create your constraints only once. For example, in the -setupConstraints method. And keep a link to the ones that need to be updated. See code below.
• In the -updateViewConstraints method, it is easy to update the top and vertical height and width constraints for the scrollViewContainer.

Here ViewController.m should look like this:

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, strong) IBOutlet UIScrollView* pageScrollView;
@property (nonatomic, strong) NSLayoutConstraint* pictureHeightConstraint;
@property (nonatomic, strong) NSLayoutConstraint* topViewWidthConstraint;
@property (nonatomic, strong) NSLayoutConstraint* topViewHeightConstraint;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    newBounds = [self sizeInOrientation:[UIApplication sharedApplication].statusBarOrientation];

    newOrientation = [UIApplication sharedApplication].statusBarOrientation;
    bodyViewHeight = 1200; // The height of the body view varies in size depending on orientation

    self.pageScrollView.translatesAutoresizingMaskIntoConstraints = NO;

    topView = [[UIView alloc] init];
    [topView setBackgroundColor:[UIColor clearColor]];
    topView.translatesAutoresizingMaskIntoConstraints = NO;
    [self.pageScrollView addSubview:topView];

    headerView = [[UIView alloc] init];
    [headerView setBackgroundColor:[UIColor redColor]];
    headerView.translatesAutoresizingMaskIntoConstraints = NO;
    [topView addSubview:headerView];

    scrollViewContainer = [[UIView alloc] init];
    [scrollViewContainer setBackgroundColor:[UIColor blueColor]];
    scrollViewContainer.translatesAutoresizingMaskIntoConstraints = NO;
    [topView addSubview:scrollViewContainer];

    bodyView = [[UIView alloc] init];
    [bodyView setBackgroundColor:[UIColor greenColor]];
    bodyView.translatesAutoresizingMaskIntoConstraints = NO;
    [topView addSubview:bodyView];

    [self setupConstraints];
}


- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)setupConstraints {
    // Remove old constraints
    [self.view removeConstraints:self.view.constraints];
    [self.pageScrollView removeConstraints:self.pageScrollView.constraints];
    [topView removeConstraints:topView.constraints];
    [scrollViewContainer removeConstraints:scrollViewContainer.constraints];

    if ((newOrientation == UIDeviceOrientationLandscapeLeft) || (newOrientation == UIDeviceOrientationLandscapeRight)) {
        pictureScrollHeight = 300;
    } else {
        pictureScrollHeight = 203;
    }

    [headerView setNeedsDisplay];
    [bodyView setNeedsDisplay];

    CGFloat topViewHeight = bodyViewHeight + 55 + pictureScrollHeight;

    //self.pageScrollView = _pageScrollView
    NSDictionary *viewsDict = NSDictionaryOfVariableBindings(_pageScrollView, topView, headerView, bodyView, scrollViewContainer);

    // pageScrollView - child to self.view
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[_pageScrollView]-0-|" options:0 metrics:nil views:viewsDict]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-    [_pageScrollView]-0-|" options:0 metrics:nil views:viewsDict]];

    // topView - child to pageScrollView
    [self.pageScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[topView]-0-|" options:0 metrics:nil views:viewsDict]];
    [self.pageScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[topView]-0-|" options:0 metrics:nil views:viewsDict]];
    NSLayoutConstraint* topViewWidthConstraint = [NSLayoutConstraint constraintWithItem:topView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:newBounds.width];
    self.topViewWidthConstraint = topViewWidthConstraint;
    [topView addConstraint:self.topViewWidthConstraint];
    NSLayoutConstraint* topViewHeightConstraint = [NSLayoutConstraint constraintWithItem:topView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:topViewHeight];
    self.topViewHeightConstraint = topViewHeightConstraint;
    [topView addConstraint:self.topViewHeightConstraint];

    // headerView - child to topView
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[headerView]-0-|" options:0 metrics:nil views:viewsDict]];
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[headerView(55.0)]" options:0 metrics:nil views:viewsDict]];

    // scrollViewContainer - child to topView
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[scrollViewContainer]-0-|" options:0 metrics:nil views:viewsDict]];
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[headerView]-0-[scrollViewContainer]" options:0 metrics:nil views:viewsDict]];
    NSLayoutConstraint* pictureHeightConstraint = [NSLayoutConstraint constraintWithItem:scrollViewContainer attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:pictureScrollHeight];
    self.pictureHeightConstraint = pictureHeightConstraint;
    [scrollViewContainer addConstraint:self.pictureHeightConstraint];

    // bodyView - child to topView
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[bodyView]-0-|" options:0 metrics:nil views:viewsDict]];
    [topView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:   [scrollViewContainer]-0-[bodyView]-0-|" options:0 metrics:nil views:viewsDict]];
}

- (void)updateViewConstraints
{
    [super updateViewConstraints];
    if ((newOrientation == UIDeviceOrientationLandscapeLeft) || (newOrientation == UIDeviceOrientationLandscapeRight)) {
        pictureScrollHeight = 300;
    } else {
        pictureScrollHeight = 203;
    }

    CGFloat topViewHeight = bodyViewHeight + 55 + pictureScrollHeight;
    self.pictureHeightConstraint.constant = pictureScrollHeight;
    self.topViewHeightConstraint.constant = topViewHeight;
    self.topViewWidthConstraint.constant = newBounds.width;
    [self.pageScrollView setNeedsUpdateConstraints];
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    newBounds = [self sizeInOrientation:toInterfaceOrientation];
}


-(CGSize)sizeInOrientation:(UIInterfaceOrientation)orientation
{
    CGSize size = [UIScreen mainScreen].bounds.size;
    UIApplication *application = [UIApplication sharedApplication];
    if (UIInterfaceOrientationIsLandscape(orientation))
    {
        size = CGSizeMake(size.height, size.width);
    }
    if (application.statusBarHidden == NO)
    {
        size.height -= MIN(application.statusBarFrame.size.width, application.statusBarFrame.size.height);
    }
    return size;
}


@end

      

        
        
        
      

    

The ScrollView will automatically size its content based on the subviews constraints added to it. Of course it only works in autorun mode.