how to show the selected image in MKAnnotation CalloutAccessoryView, swift 2.2

Question

How can I set my map MKAnnotation CalloutAccessoryView to show the selected image mapped out from my realm database (with icons and buttons on either side, as the left and right calloutAccessory?). I also need it to recognize the class/member for other functions on my MapViewController here? The mapping of the data and left and right callout accessories are working fine, but I can't figure out how to add the selected image, so it show up as a large poster-style image on the callout (with the small icons & buttons on either side).

The image is SpecimenAnnotation.objectPoster

The SpecimenAnnotation (which is working fine to map the data) and 'objectPoster' value is the selected (and mapped) Annotation from the class Specimen, included in my file Specimen.swift, like this;

 class Specimen: Object{
  dynamic var name = ""
 dynamic var objectPoster = ""
 dynamic var latitude = 0.0
 dynamic var longitude = 0.0
 dynamic var created = NSDate()
 dynamic var category: Category!
}

In my MapViewController, on the line 'annotationView.detailCalloutAccessoryView = UIImageView(image: SpecimenAnnotation.objectPoster)' I am getting a red alert error "instance member 'objectPoster' cannot be used on type 'Specimen Annotation'

I am a beginner. Would greatly appreciate your suggestions. Any ideas?

Here are the code blocks regarding this data and error:

       // Create annotations for each one
    for specimen in specimens { // 3
        let coord = CLLocationCoordinate2D(latitude: specimen.latitude, longitude: specimen.longitude);

        let specimenAnnotation = SpecimenAnnotation(coordinate: coord,  poster: specimen.objectPoster, subtitle: specimen.category.name, specimen: specimen)

        mapView.addAnnotation(specimenAnnotation) // 4
    }
   }

}

 //MARK: - MKMapview Delegate
 extension MapViewController: MKMapViewDelegate {

func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView? {

    guard let subtitle = annotation.subtitle! else { return nil }

    if (annotation is SpecimenAnnotation) {
        if let annotationView = mapView.dequeueReusableAnnotationViewWithIdentifier(subtitle) {
            return annotationView
        } else {

            let currentAnnotation = annotation as! SpecimenAnnotation

            let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: subtitle)
            annotationView.image = UIImage(named:"IconStudent")
            annotationView.enabled = true
            annotationView.canShowCallout = true                      

            // ERROR message here> 
            annotationView.detailCalloutAccessoryView = UIImageView(image: SpecimenAnnotation.objectPoster)

            // right accessory view
            let infoButton = UIButton(type: UIButtonType.InfoDark)
            // Left accessory view
            let image = UIImage(named: "button50")
            let specimenButton = UIButton(type: .Custom)
            specimenButton.frame = CGRectMake(0, 0, 30, 30)
            specimenButton.setImage(image, forState: .Normal)
            annotationView.rightCalloutAccessoryView = infoButton
            annotationView.leftCalloutAccessoryView = specimenButton

            if currentAnnotation.title == "Empty" {
                annotationView.draggable = true
            }              
            return annotationView
        }
    }
    return nil

}

Answer 1

I solved it, by pulling the value into the currentAnnotation, and adding it in a UIImageView on the DetailCalloutAccessoryView

func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView? {

    guard let subtitle = annotation.subtitle! else { return nil }

    if (annotation is SpecimenAnnotation) {
        if let annotationView = mapView.dequeueReusableAnnotationViewWithIdentifier(subtitle) {
            return annotationView
        } else {

            let currentAnnotation = annotation as! SpecimenAnnotation

            let currentImage = currentAnnotation.objectPoster!


            let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: subtitle)
            }

            annotationView.enabled = true
            annotationView.canShowCallout = true

            // right accessory view
            let calloutInfoButton = UIButton(type: UIButtonType.InfoDark)

            // Left accessory view
            let calloutLeftImage = UIImage(named: "button50p")
            let calloutLeftButton = UIButton(type: .Custom)
            calloutLeftButton.frame = CGRectMake(0, 0, 30, 30)
            calloutLeftButton.setImage(calloutLeftImage, forState: .Normal)

            //show Image on callout Accessory

            let url = NSURL(string: currentImage)
            let data = NSData(contentsOfURL: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check
            //annotationView.image = UIImage(data: data!)
            let calloutImage = UIImage(data:data!)

            annotationView.detailCalloutAccessoryView = UIImageView(image: calloutImage)

            annotationView.rightCalloutAccessoryView = calloutInfoButton
            annotationView.leftCalloutAccessoryView = calloutLeftButton

            if currentAnnotation.title == "Empty" {
                annotationView.draggable = true
            }
            return annotationView
        }
    }
    return nil

}