How do I enable directional lock for a UIScrollView?

Question

I have a UIScrollView with a UIView inside. I want to lock the x-axis so that the view is only scrolled vertically. How do I enable directional locking?

Answer 1

First, set the UIScrollView's contentSize to have a width that is equal to or less than the width of the UIScrollView's frame.

Next, set UIScrollView's alwaysBounceHorizontal to NO. This will prevent the scroll view from "rubber banding" even though you've told it there's no more horizontal content to display.

UIScrollView *scrollView;
CGSize size = scrollView.contentSize;
size.width = CGRectGetWidth(scrollView.frame);
scrollView.contentSize = size;
scrollView.alwaysBounceHorizontal = NO;

It doesn't matter what's actually inside the scroll view.

Swift 5.0

let scrollView = UIScrollView() // Or however you want to initialize it
var size = scrollView.contentSize
size.width = scrollView.frame.width
scrollView.contentSize = size
scrollView.alwaysBounceHorizontal = false