As I understand, the default behaviour of UISearchController is:
Swift 3 Version:
If your searchResultController is not nil and you are using a separate table view controller to show the search results, then you can make that table view controller conform to UISearchResultUpdating and in the updateSearchResults function, you can simply unhide the view.
func updateSearchResults(for searchController: UISearchController) {
view.hidden = false
}
Swift 4 Version:
func updateSearchResults(for searchController: UISearchController) {
view.isHidden = false
}