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've found that this is the simplest and most flexible option (it works for UICollectionView and UITableView as well).

override func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer) {

    switch velocity {
    case _ where velocity.y < 0:
        // swipes from top to bottom of screen -> down
        trackingDirection = .down
    case _ where velocity.y > 0:
        // swipes from bottom to top of screen -> up
        trackingDirection = .up
    default: trackingDirection = .none
    }
}

Where this doesn't work though, is if there is 0 velocity - in which case you'll have no choice but to use the accepted answer's stored property solution.