滚动视图的水平居中内容

Question

I have a standard view embedded inside a scroll view and I am using Auto Layout. All is working fine, and I am almost done with it. There is just one small problem. My content view has a fixed height of 536 points, so in an iPhone 6 it is fully displayed without the need of scrolling, while in an iPhone 4S I have to scroll to view additional content.

My problem is that the view is not horizontally centered is the iPhone 6 so it displays the extra space at the bottom (I filled it with grey color for clarity), as shown in the picture below (that is the underlying scroll view).

My question is: how can I horizontally center the content view without messing up the constraints? Currently the scroll view is pinned at the four borders of the view controller and the content view is pinned to the four borders of the scroll view.

I am glad to provide any other information you need to help me solve the problem.

EDIT: This is what it worked for me

CGFloat superViewHeight = self.view.bounds.size.height;
CGFloat scrollViewHeight = self.scrollView.bounds.size.height;

if (superViewHeight > scrollViewHeight)
    self.topConstraint.constant += (superViewHeight - scrollViewHeight) / 4;

Answer 1

You should manually adjust top constraint if your content view doesn't need scrolling.

CGFloat scrollViewHeight = CGRectGetHeight(scrollView.bounds);
CGFloat contentViewHeight = CGRectGetHeight(contentView.bounds);

if (scrollViewHeight >= contentViewHeight)
{
    topConstraint.constant += ((scrollViewHeight - contentViewHeight) / 2.f);
}