iOS/Swift Tip - Add a sticky and stretchy top cell to your UITableView

stretchy_sticky_top_cell.swift

// For more information, visit:
// https://gtiapps.com/?p=4482

// It is pressumed that you have added a table view (UITableView) to your view controller,
// and that you have set the view controller as the delegate of the tableview (tableView.delegate = self).

// Two different approaches are provided:

// Approach #1
// Implement the following scroll view delegate method:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView.contentOffset.y < 0.0 {
        if let cell = tableView.cellForRow(at: IndexPath(row: 0, section: 0)) {
            cell.frame.origin.y = scrollView.contentOffset.y
            let originalHeight: CGFloat = 280.0            
            cell.frame.size.height = originalHeight + scrollView.contentOffset.y * (-1.0)
        }
    }
}

// Approach #2:
// Declare the following property in your class:
var lastContentOffset = CGPoint.zero

// Implement the following scroll view delegate method:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView.contentOffset.y < 0.0 {
        if let cell = tableView.cellForRow(at: IndexPath(row: 0, section: 0)) {
            let deltaY = CGFloat(fabsf(Float(scrollView.contentOffset.y)) - fabsf(Float(lastContentOffset.y)))            
            cell.frame = CGRect(x: 0.0, y: scrollView.contentOffset.y, width: cell.frame.size.width, height: cell.frame.size.height + deltaY)
            lastContentOffset = scrollView.contentOffset
        }
    }
}