Change of scene class causes error, Xcode / Swift - xcode

Question

I am trying to make a small iPad application which features an 'About' page. I have run into an issue when I try to change the class of the about page scene which is displayed modally, as the application crashes when the user tries to access this page. I wish to change its class to "ViewController", which is the same class as my main window (map view), to create actions from buttons on the 'About' page.
Currently I am unable to ctrl+drag to the .Swift file from the About page unless I change its class. Not sure why this is happening :(
The error printed to the console is as follows:
fatal error: unexpectedly found nil while unwrapping an Optional value
0 specialised_fatalErrorMessage(StaticString, StaticString, StaticString, Uint) -> () –
Here is my storyboard with scenes:
Here is the full ViewController.Swift code:
import UIKit
import MapKit
import CoreLocation
class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate, UISearchBarDelegate, UIPopoverPresentationControllerDelegate {
var location: CLLocation!
let locationManager = CLLocationManager()
// Map variables
var searchController:UISearchController!
var annotation:MKAnnotation!
var localSearchRequest:MKLocalSearchRequest!
var localSearch:MKLocalSearch!
var localSearchResponse:MKLocalSearchResponse!
var error:NSError!
var pointAnnotation:MKPointAnnotation!
var pinAnnotationView:MKPinAnnotationView!
#IBOutlet weak var mapView: MKMapView!
#IBOutlet weak var segmentedControl: UISegmentedControl!
#IBOutlet weak var showSearchBar: UIBarButtonItem!
#IBOutlet weak var addButton: UIBarButtonItem!
#IBOutlet weak var moreStuff: UIBarButtonItem!
#IBAction func addButton(sender: AnyObject) {
let annotation = MKPointAnnotation()
annotation.coordinate = CLLocationCoordinate2D(latitude: self.mapView.userLocation.coordinate.latitude, longitude: self.mapView.userLocation.coordinate.longitude)
self.mapView.addAnnotation(annotation)
self.locationManager.startUpdatingLocation()
}
#IBAction func showSearchBar(sender: UIBarButtonItem!) {
searchController = UISearchController(searchResultsController: nil)
searchController.hidesNavigationBarDuringPresentation = false
self.searchController.searchBar.delegate = self
presentViewController(searchController, animated: true, completion: nil)
}
#IBAction func moreStuff(sender: AnyObject) {
self.performSegueWithIdentifier("showMoreStuff", sender:self)
}
#IBAction func refresh(sender: AnyObject) {
self.locationManager.startUpdatingLocation()
}
#IBAction func segmentedControl(sender: UISegmentedControl!) {
if sender.selectedSegmentIndex == 0{
mapView.mapType = MKMapType.Standard
}
else if sender.selectedSegmentIndex == 1{
mapView.mapType = MKMapType.Satellite
}
else if sender.selectedSegmentIndex == 2{
mapView.mapType = MKMapType.Hybrid
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.locationManager.delegate = self
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
self.locationManager.requestWhenInUseAuthorization()
self.locationManager.startUpdatingLocation()
self.mapView.showsUserLocation = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// location delegate methods
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location = locations.last
let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))
self.mapView.setRegion(region, animated: true)
self.locationManager.stopUpdatingLocation()
}
func locationManager(manager: CLLocationManager, didFailWithError error: NSError)
{
print("Error code: " + error.localizedDescription)
}
func searchBarSearchButtonClicked(searchBar: UISearchBar){
searchBar.resignFirstResponder()
dismissViewControllerAnimated(true, completion: nil)
if self.mapView.annotations.count != 0{
annotation = self.mapView.annotations[0]
self.mapView.removeAnnotation(annotation)
}
localSearchRequest = MKLocalSearchRequest()
localSearchRequest.naturalLanguageQuery = searchBar.text
localSearch = MKLocalSearch(request: localSearchRequest)
localSearch.startWithCompletionHandler { (localSearchResponse, error) -> Void in
if localSearchResponse == nil{
let alertController = UIAlertController(title: nil, message: "No Such Place", preferredStyle: UIAlertControllerStyle.Alert)
alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alertController, animated: true, completion: nil)
return
}
self.pointAnnotation = MKPointAnnotation()
self.pointAnnotation.title = searchBar.text
self.pointAnnotation.coordinate = CLLocationCoordinate2D(latitude: localSearchResponse!.boundingRegion.center.latitude, longitude: localSearchResponse!.boundingRegion.center.longitude)
self.pinAnnotationView = MKPinAnnotationView(annotation: self.pointAnnotation, reuseIdentifier: nil)
self.mapView.centerCoordinate = self.pointAnnotation.coordinate
}
}
}
I am new to Swift so any help is really appreciated. Thanks!
Edit:
This is the error screen presented to me once the app crashes:

Answer 1

I haven't used mapKit but I still try.
Looking at your error your getting a nil crash, which indicates one of your properties is nil yet you try to use it.
Having a quick read through your code it seams you haven't initialised
var localSearchResponse....
Again i don't know the MK API very well so I am not 100 sure what I'm saying is relevant.
Have you checked that all your IBOutlets are properly connected?
On which line do you get the crash when this happens? Do you get the crash before or after changing to the abouts page?