Question

I can’t seem to be able to add a disclosure button to my map annotations.

I implemented the MKMapViewDelegate to my view controller as well. What am I missing?

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKPinAnnotationView *mapPin = nil;
    if(annotation != map.userLocation) 
    {
        static NSString *defaultPinID = @"defaultPin";
        mapPin = (MKPinAnnotationView *)[map dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
        if (mapPin == nil )
            mapPin = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:defaultPinID];

        mapPin.canShowCallout = YES;
        UIButton *infoButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        mapPin.rightCalloutAccessoryView = infoButton;

    }
    return mapPin;
}

Answer 1

That code should work but check the following:

• Is the map view’s delegate property set? Declaring that the view controller implements the MKMapViewDelegate protocol does not actually tell the map view which object is implementing the delegate methods. In code, do map.delegate = self; or in IB connect the delegate outlet to File’s Owner.
• Is the annotation’s title property set to non-blank? If the title is blank, no callout will show.

Also, unrelated but, when the dequeue returns an annotation view, you should update its annotation property to the current annotation (it might have been used for another annotation previously). Additionally, unless you’re using ARC, you should also autorelease the view.

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKPinAnnotationView *mapPin = nil;
    if(annotation != map.userLocation) 
    {
        static NSString *defaultPinID = @"defaultPin";
        mapPin = (MKPinAnnotationView *)[map dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
        if (mapPin == nil )
        {
            mapPin = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation 
                         reuseIdentifier:defaultPinID] autorelease];
            mapPin.canShowCallout = YES;
            UIButton *infoButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            mapPin.rightCalloutAccessoryView = infoButton;
        }
        else
            mapPin.annotation = annotation;

    }
    return mapPin;
}