iOS trouble accessing property of MKAnnotation

Question

I can't seem to access a custom MKAnnotation property inside of mapView:viewForAnnotation delegate method. As I understand it, the method takes annotations as values. I'm trying to target the properties of each annotation that gets passed in.

Code

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation
{
    //This actually returns a proper coordinate
    NSLog(@"%f", annotation.coordinate.latitude);

    //This gives me an error: Property 'annotationMarker' not found on object of type '__strong id<MKAnnotation>'
    NSLog(@"%@", annotation.annotationMarker);

    MKAnnotationView *testPin = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"current"];

    testPin.image = [UIImage imageNamed:[[testArray objectAtIndex:1]annotationMarker]];

    return testPin;
}

I thought maybe the custom property wasn't set correctly, but I'm able to log the property values for these annotations in other parts of the code.

Am I making some kind of syntax error? Does this delegate method strip out custom properties somehow?

Answer 1

You need to cast to your custom MKAnnotation-conformant class, e.g.

CustomAnnotation *customAnnotation = (CustomAnnotation *)annotation;
NSLog(@"%@", customAnnotation.annotationMarker);