UIScrollView wrong offset with Auto Layout

Question

I have a fairly simple view configuration:

A UIViewController, with a child UIScrollView and a UIImageView in this UIScr

Answer 1

Looks like the problem solved with the dispatch_async during the viewWillAppear:

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

    CGPoint originalContentOffset = self.scrollView.contentOffset;
    self.scrollView.contentOffset = CGPointZero;

    dispatch_async(dispatch_get_main_queue(), ^{
        self.scrollView.contentOffset = originalContentOffset;
    });
}

Answer 2

Add a global property contentOffset and save the current contentOffset in viewDidDisappear. Once you return the method viewDidLayoutSubviews will be called and you can set your original contentOffset.

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];
    [self.scrollView setContentOffset:self.contentOffset animated:FALSE];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
    self.contentOffset = self.scrollView.contentOffset;
    [self.scrollView setContentOffset:CGPointMake(0, 0) animated:FALSE];
}

Answer 3

I had a similar problem using a UIScrollView in a UIViewController with a top extra space that was not visible in Storyboard. The solution for me was to uncheck the "Adjust Scroll View Insets" on the ViewController storyboard properties : see answer Extra Space (inset) in Scroll View at run time

Answer 4

For me I went to the IB clicked my view controller that contains the scroll view. Then I went to Attribute Inspector -> View Controller -> Extend Edges -> Uncheck "Under Top Bars" and "Under Bottom Bars".

Answer 5

Simple solution found, Just put

[self setAutomaticallyAdjustsScrollViewInsets:NO];

in your ViewControllers viewDidLoad method

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    [self setAutomaticallyAdjustsScrollViewInsets:NO];
}

Answer 6

Yeah, something strange happened with UIScrollView in pure autolayout environment. Re-reading the iOS SDK 6.0 release notes for the twentieth time I found that:

Note that you can make a subview of the scroll view appear to float (not scroll) over the other scrolling content by creating constraints between the view and a view outside the scroll view’s subtree, such as the scroll view’s superview.

Solution

Connect your subview to the outer view. In another words, to the view in which scrollview is embedded.

As IB does not allow us set up constraints between the imageView and a view outside the scroll view’s subtree, such as the scroll view’s superview then I've done it in code.

- (void)viewDidLoad {
    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
    [self.view removeConstraints:[self.view constraints]];
    [self.scrollView removeConstraints:[self.scrollView constraints]];
    [self.imageView removeConstraints:[self.imageView constraints]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[_scrollView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_scrollView)]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_scrollView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_scrollView)]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[_imageView(700)]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_imageView)]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_imageView(1500)]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_imageView)]];
}

And vau! It works!