How to disable horizontal scrolling of UIScrollView?

You have to set the contentSize property of the UIScrollView. For example, if your UIScrollView is 320 pixels wide (the width of the screen), then you could do this:

CGSize scrollableSize = CGSizeMake(320, myScrollableHeight);
[myScrollView setContentSize:scrollableSize];

The UIScrollView will then only scroll vertically, because it can already display everything horizontally.

UPDATED: (After @EranMarom pointed out on his comment)

You can stop horizontal scrolling or vertical scrolling in the ScrollViewDelegate Method. Here it is how,

Stops Horizontal Scrolling:

If you want to scroll horizontally, then you need to increase the contentOffset.x. Preventing that stops the scrollview scroll in horizontal direction.

- (void)scrollViewDidScroll:(UIScrollView *)sender {
    sender.contentOffset.x = 0.0
}

Stops Vertical Scrolling:

If you want to scroll vertically, then you need to increase the contentOffset.y. Preventing that stops the scrollview scroll in vertical direction.

- (void)scrollViewDidScroll:(UIScrollView *)sender {
    sender.contentOffset.y = 0.0
}

Above code prevents the changes in x and y of a scrollview contentOffset and it leads to stop the scrolling in scrollViewDidScroll: method.

since iOS7 use

self.automaticallyAdjustsScrollViewInsets = NO;

//and create you page scroller with 3 pages

    self.pageView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
    [self.pageView setContentSize:CGSizeMake(self.view.frame.size.width*3, self.view.frame.size.height)];
    [self.pageView setShowsVerticalScrollIndicator:NO];
    [self.pageView setPagingEnabled:YES];
    [self.view addSubview:self.pageView];

Swift solution

Create two outlets, one for your view and one for your scroll view:

@IBOutlet weak var myView: UIView!
@IBOutlet weak var scrollView: UIScrollView!

Then in your viewDidLayoutSubviews you can add the following code:

let scrollSize = CGSize(width: myView.frame.size.width, 
                        height: myView.frame.size.height)
scrollView.contentSize = scrollSize

What we've done is collected the height and width of the view and set the scrollViews content size to match it. This will stop your scrollview from scrolling horizontally.

More Thoughts:

CGSizeMake takes a width & height using CGFloats. You may need to use your UIScrollViews existing height for the second parameter. Which would look like this:

let scrollSize = CGSize(width: myView.frame.size.width, 
                        height: scrollView.contentSize.height)

In my case, with Swift 4.2 you can use:

Disable vertical scroll:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    scrollView.contentOffset.y = 0.0
}

Disable horizontal scroll:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    scrollView.contentOffset.x = 0.0
}