Move a view when scrolling in UITableView

Question

I have a UIView with a UITableView below it:

Answer 1

You can make it like this:

Add these as your class variables:

private let NUMBER_OF_ROWS: Int = 256
private let ROW_HEIGHT: CGFloat = 75.0
private let MINIMUM_CONSTANT_VALUE: CGFloat = -150.0 /// This is the hidable view's height

@IBOutlet weak var hidableViewTopConstraint: NSLayoutConstraint! /// This is an outlet from your storyboard
private var lastContentOffset: CGFloat = 0.0

This goes on your viewDidLoad():

tableView.delegate = self

And then you add this as an extension for your view controller:

extension ViewController: UIScrollViewDelegate {

    func scrollViewDidScroll(_ scrollView: UIScrollView) {

        let delta = tableView.contentOffset.y - lastContentOffset

        let canScrollUp: Bool =
            delta < 0 &&
              hidableViewTopConstraint.constant < 0 &&
                scrollView.contentOffset.y < 0



        let canScrollDown: Bool =
            delta > 0 &&
              hidableViewTopConstraint.constant > MINIMUM_CONSTANT_VALUE &&
                tableView.contentOffset.y > 0


        if canScrollUp || canScrollDown{

            hidableViewTopConstraint.constant -= delta
            tableView.contentOffset.y -= delta

        }

        lastContentOffset = tableView.contentOffset.y

    }
}

But note that the scroll mechanism will only work when the TableView is scrolled. The top view wont collapse or expand if you scroll it.

I made an example project you can check, it is called iOSFixedHeaderList