searchController = UISearchController(searchResultsController: nil)
    searchController?.searchBar.delegate = self
    searchController?.dimsBackgroundDuringPresentation = true
    searchController?.searchResultsUpdater = self
    navigationItem.searchController = searchController

var didPerformSearch: Bool = false

if didPerformSearch == true {
   yourSearchBar.isHidden = true
}else{
   yourSearchBar.isHidden = false
}