I have a view for the iPhone that is basically split in two, with an informational display in the top half, and a UITableView for selecting actions in the bottom half. The prob
I made a UITableView extension that displays a native style separator on top of the UITableView, while the table gets scrolled.
Here's the code (Swift 3)
fileprivate var _topSeparatorTag = 5432 // choose unused tag
extension UITableView {
fileprivate var _topSeparator: UIView? {
return superview?.subviews.filter { $0.tag == _topSeparatorTag }.first
}
override open var contentOffset: CGPoint {
didSet {
guard let topSeparator = _topSeparator else { return }
let shouldDisplaySeparator = contentOffset.y > 0
if shouldDisplaySeparator && topSeparator.alpha == 0 {
UIView.animate(withDuration: 0.15, animations: {
topSeparator.alpha = 1
})
} else if !shouldDisplaySeparator && topSeparator.alpha == 1 {
UIView.animate(withDuration: 0.25, animations: {
topSeparator.alpha = 0
})
}
}
}
// Adds a separator to the superview at the top of the table
// This needs the separator insets to be set on the tableView, not the cell itself
func showTopSeparatorWhenScrolled(_ enabled: Bool) {
if enabled {
if _topSeparator == nil {
let topSeparator = UIView()
topSeparator.backgroundColor = separatorColor?.withAlpha(newAlpha: 0.85) // because while scrolling, the other separators seem lighter
topSeparator.translatesAutoresizingMaskIntoConstraints = false
superview?.addSubview(topSeparator)
topSeparator.leftAnchor.constraint(equalTo: self.leftAnchor, constant: separatorInset.left).isActive = true
topSeparator.rightAnchor.constraint(equalTo: self.rightAnchor, constant: separatorInset.right).isActive = true
topSeparator.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
let onePixelInPoints = CGFloat(1) / UIScreen.main.scale
topSeparator.heightAnchor.constraint(equalToConstant: onePixelInPoints).isActive = true
topSeparator.tag = _topSeparatorTag
topSeparator.alpha = 0
superview?.setNeedsLayout()
}
} else {
_topSeparator?.removeFromSuperview()
}
}
func removeSeparatorsOfEmptyCells() {
tableFooterView = UIView(frame: .zero)
}
}
To enable it, simply call tableView.showTopSeparatorWhenScrolled(true)
after you set your delegate
for your UITableView