Defining the title and the subtitle text of an annotation in Swift - ios

Question

I was watching a course on how to edit maps in Swift and add annotations, but unfortunately the instructor did not talk about how to edit the title and the subtitle of an annotation after adding one on the map, so I wanted to go a little bit further and edit them with my very simple knowledge in Swift.
Here's the code:
import UIKit
import MapKit
class ViewController: UIViewController, MKMapViewDelegate {
#IBOutlet weak var mapView: MKMapView!
//add
#IBOutlet weak var titleText: UITextField!
#IBOutlet weak var subtitleText: UITextField!
#IBOutlet weak var buttonAdd: UIButton!
//add
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
//add
subtitleText.alpha = 0
titleText.alpha = 0
buttonAdd.hidden = true
//add
// 51.498340, -0.153257
var latitude:CLLocationDegrees = 51.498340
var longitude:CLLocationDegrees = -0.153257
var latDelta:CLLocationDegrees = 0.02
var lonDelta:CLLocationDegrees = 0.02
var span:MKCoordinateSpan = MKCoordinateSpanMake(latDelta, lonDelta)
var location:CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
var region:MKCoordinateRegion = MKCoordinateRegionMake(location, span)
mapView.setRegion(region, animated: true)
var annotation = MKPointAnnotation()
annotation.coordinate = location
annotation.title = "Belgravia"
annotation.subtitle = "I love you!"
mapView.addAnnotation(annotation)
var uilpgr = UILongPressGestureRecognizer(target: self, action: "action:")
uilpgr.minimumPressDuration = 2.0
mapView.addGestureRecognizer(uilpgr)
}
let newAnnotation = MKPointAnnotation()
func action(gestureRecognizer:UIGestureRecognizer) {
var touchPoint = gestureRecognizer.locationInView(self.mapView)
var newCoordinate:CLLocationCoordinate2D = mapView.convertPoint(touchPoint, toCoordinateFromView: self.mapView)
newAnnotation.coordinate = newCoordinate
titleText.alpha = 1
subtitleText.alpha = 1
buttonAdd.hidden = false
mapView.addAnnotation(newAnnotation)
var uilpgr = UILongPressGestureRecognizer(target: self, action: "action:")
uilpgr.minimumPressDuration = 2.0
}
func addPoint(sender: AnyObject) {
newAnnotation.title = titleText.text
newAnnotation.subtitle = subtitleText.text
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Every time I try to write text inside these two and then press the addPoint button in the iOS simulator it'll crash unexpectedly
[Maps.ViewController button:]: unrecognized selector sent to instance...