override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
sizeHeaderToFit()
}
private func sizeHeaderToFit() {
let headerView = tableView.tableHeaderView!
headerView.setNeedsLayout()
headerView.layoutIfNeeded()
let height = headerView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height
var frame = headerView.frame
frame.size.height = height
headerView.frame = frame
tableView.tableHeaderView = headerView
}
More details can be found here