How to get UIScrollView vertical direction in Swift?

Question

How can I get the scroll/swipe direction for up/down in a VC?

I want to add a UIScrollView or something else in my VC that can see if the user swipes/scrolls up or d

Answer 1

I used Victor's answer with a minor improvement. When scrolling past the end or beginning of the scroll, and then getting the bounce back effect. I have added the constraint by calculating scrollView.contentSize.height - scrollView.frame.height and then limiting the scrollView.contentOffset.y range to be greater than 0 or less than scrollView.contentSize.height - scrollView.frame.height, no changes are made when bouncing back.

func scrollViewDidScroll(_ scrollView: UIScrollView) {

    if lastContentOffset > scrollView.contentOffset.y && lastContentOffset < scrollView.contentSize.height - scrollView.frame.height {
        // move up
    } else if lastContentOffset < scrollView.contentOffset.y && scrollView.contentOffset.y > 0 {
        // move down
    }

    // update the new position acquired
    lastContentOffset = scrollView.contentOffset.y
}