iPhone Core Location: DIfferentiate pin for custom pin image

I am using

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation{

to draw my own image for a custom pin. I would like to use a different image for different pins. I was wondering how I could differentiate which pin was calling this function.

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation{

    MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"MyPin"];
    annView.canShowCallout = YES;

    annView.calloutOffset = CGPointMake(-5, 5);

    if ([annView.annotation.title isEqualToString:myLocation]) {
        UIImage *pinI开发者_如何学Pythonmage = [UIImage imageNamed:@"myLocationImage.png"];
        [annView setImage:pinImage];
    } else {
        UIImage *pinImage = [UIImage imageNamed:@"resImage.png"];
        [annView setImage:pinImage];
    }

    return annView;
}

EDIT: Revisiting this for a new project, I realized creating different pin classes was wasteful. A better implementation would be to set the pin type, then read it out of the annotation of the MKAnnotationView. Example below.

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>) annotation {

    MKPinAnnotationView *pin = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"PinID"];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    [button addTarget:self action:@selector(viewStoreDetails:) forControlEvents:UIControlEventTouchDown];

    pin.rightCalloutAccessoryView = button;
    pin.canShowCallout = YES;
    pin.calloutOffset = CGPointMake(-5, 5);

    Annotation *a = (Annotation *)pin.annotation;

    int i = a.locationType;

    switch (i) {
        case RETAIL:
            pin.image = [UIImage imageNamed:@"pin_retail.png"];
            break;
        case OUTLET:
            pin.image = [UIImage imageNamed:@"pin_outlet.png"];
            break;
        case COMING_SOON:
            pin.image = [UIImage imageNamed:@"pin_coming_soon.png"];
            break;
        case MY_LOCATION:
            pin.image = [UIImage imageNamed:@"pin_my_location.png"]; 
            break;
            pin.image = [UIImage imageNamed:@"pin_retail.png"];
        default:
            break;
    }

    return [pin autorelease];
}

annView.annotation.title did the trick.