title: Google Maps GMSGroundOverlay delegate with Swift
body: <p>I'm having an issue using objective-c delegates with swift. I want to overlay an image on google maps, then execute some other code if the overlay is touched. I was able to overlay the image and display maps, but I can't get the other code to execute for the tap event. Xcode 6 doesn't autocomplete objective-c delegates for swift, so I tried translating the original to get it to work according to this <a href="https://stackoverflow.com/questions/24189946/call-facebook-delegates-in-swift">post</a>. Anyone know how to get these to work?</p>
  
  <p>Here is my code: </p>
  
  <pre><code>
  class ViewController: UIViewController, GMSMapViewDelegate {
  
      override func viewDidLoad() {
          super.viewDidLoad()
          // Do any additional setup after loading the view, typically from a nib.
  
          /* MapView inital values & dependencies */
          let initialLocation = CLLocationCoordinate2DMake(37.78, -122.41)
          let initialDirection = CLLocationDirection()
          let camera = GMSCameraPosition.cameraWithTarget(initialLocation, zoom: 10)
  
          /* Set up MapView */
          var mapView_ = GMSMapView(frame: CGRectZero)
          mapView_.camera = camera
          mapView_.myLocationEnabled = true
          self.view = mapView_
          mapView_.delegate = self
  
  
          let southwest = CLLocationCoordinate2DMake(37.72, -122.35)
          let northeast = CLLocationCoordinate2DMake(37.80,-122.52)
  
          let overlayBounds = GMSCoordinateBounds(coordinate: southwest, coordinate: northeast)
  
          /* add opacity and overlay */
          var img = UIImage(named:"image.png")
          img = addOpacity(img, 0.5)
          var overlay = GMSGroundOverlay(bounds: overlayBounds, icon: img)
  
  
          overlay.tappable = true
          overlay.bearing = 0
          overlay.map = mapView_
  
      }
  
      override func didReceiveMemoryWarning() {
          super.didReceiveMemoryWarning()
  
          // Dispose of any resources that can be recreated.
      }
  
      // - (void)mapView:(GMSMapView *)mapView didTapOverlay:(GMSOverlay *)overlay;
  
      func mapView(mapView: GMSMapView, overlay: GMSOverlay){
          //other code here...
      }
  
  </code></pre>