Search Display Controller causing crash - uitableview

Question

I am trying to set up a searchBar with a TableView so I can filter through the table view, I am trying to do it all programmatically. Although my code keeps sending back the error: unexpectedly found nil while unwrapping an Optional value. The error is inside the func numberOfRowsInSection, I have marked it. it is to do with the SearchDisplayController, it is saying it is nil I think? code:
struct UserMatches {
var finalMatchesName : String
var finalMatchesAge : Int
var finalMatchesLocation : PFGeoPoint
var finalMatchesImage : NSData
}
class Matches: UIViewController, UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate, UISearchDisplayDelegate {
var tableView = UITableView()
var searchBar = UISearchBar()
var userMatches = [UserMatches]()
var filterUsers = [UserMatches]()
override func viewDidLoad() {
super.viewDidLoad()
createTableView()
}
func filterContentForSearchText(searchText: String) {
self.filterUsers = self.userMatches.filter({(user1: UserMatches) -> Bool in
let stringMatch = user1.finalMatchesName.rangeOfString(searchText)
return (stringMatch != nil)
})
}
func searchDisplayController(controller: UISearchDisplayController!, shouldReloadTableForSearchString searchString: String!) -> Bool {
self.filterContentForSearchText(searchString)
return true
}
func createTableView() {
tableView.sizeToFit()
tableView.dataSource = self
tableView.delegate = self
tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
searchBar.sizeToFit()
searchBar.delegate = self
searchBar.showsScopeBar = true
searchBar.searchBarStyle = UISearchBarStyle.Minimal
searchBar.showsCancelButton = true
searchBar.returnKeyType = UIReturnKeyType.Search
tableView.tableHeaderView = searchBar
var searchDispCont = UISearchDisplayController(searchBar: searchBar, contentsController: nil)
searchDispCont.delegate = self;
searchDispCont.searchResultsDataSource = self;
searchDispCont.searchResultsDelegate = self;
self.view.addSubview(tableView)
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if tableView == self.searchDisplayController!.searchResultsTableView { //fatal error: unexpectedly found nil while unwrapping an Optional value
return self.filterUsers.count
} else {
return self.userMatches.count
}
}
}

Answer 1

Yes, your view controller's searchDisplayController property is of type UISearchDisplayController? (an optional), and is nil inside tableView(_:numberOfRowsInSection:). When you force unwrap an optional using !, your app will throw a runtime exception (the one you're seeing) when the value is nil.
The reason the property is nil is that you are creating it programmatically and specifying nil for the contentsController argument. This should most likely be:
var searchDispCont = UISearchDisplayController(searchBar: searchBar, contentsController: self)
This will implicitly assign it to your view controller's searchDisplayController property.
Also, it is worth noting that UISearchDisplayController and UISearchDisplayDelegate are deprecated in iOS 8, so you should instead be using UISearchController.