UISearchController not showing - ios

Question

I am working on Swift 3.1, I want a simple search functionality where the search results will show in a popOver manner below the search bar. This is a native offering and should be available using UISearchController. But even after my repeated trials, I could not achieve this. Am I missing something?
I have mentioned the resultsController. Implemented the required delegates and even the data us fed to it. But still its not shown.
Any help will be greatly appreciated. Thanks.
Code:
func initiateView() {
resultsController = ResultsController()
resultsController.table.dataSource = self
searchController = UISearchController.init(searchResultsController: resultsController)
self.view.addSubview(searchController.searchBar)
searchController.searchResultsUpdater = self
searchController.delegate = self
searchController.dimsBackgroundDuringPresentation = false // default is YES
searchController.searchBar.delegate = self // so we can monitor text changes + others
definesPresentationContext = true
feedTable = UITableView()
feedTable.delegate = self
feedTable.dataSource = self
feedTable.separatorStyle = .singleLineEtched
feedTable.register(UITableViewCell.self, forCellReuseIdentifier: "SomeCell")
self.view.addSubview(feedTable)
feedTable.pinToSuperview([.Left, .Right, .Bottom])
feedTable.pinToSuperviewTop(withInset: 50, priority: 100)
}
func updateSearchResults(for searchController: UISearchController)
{
if let searchString = searchController.searchBar.text{
let resultsController = searchController.searchResultsController as! ResultsController
resultsController.resultsArray = feedArray.filter({$0 .contains(searchString)})
resultsController.table.reloadData()
}
}