MKPointAnnotation won't change colors

Question

I need to change the color for an MKPointAnnotation object, but the method I wrote seems to only generate red pins. The method works fine, but when I call the function, passing the parameter of one of the given constant, all pins that appear on the map are red (the default). Any thoughts? Code below.

    -(MKAnnotationView*) returnPointView: (CLLocationCoordinate2D) location andTitle: (NSString*) title andColor: (int) color{
        /*Method that acts as a point-generating machine. Takes the parameters of the location, the title, and the color of the 
         pin, and it returns a view that holds the pin with those specified details*/

        MKPointAnnotation *resultPin = [[MKPointAnnotation alloc] init];
        MKPinAnnotationView *result = [[MKPinAnnotationView alloc] initWithAnnotation:resultPin reuseIdentifier:Nil];
        [resultPin setCoordinate:location];
        resultPin.title = title;
        result.pinColor = color;
        return result;
        }

//Function that calls above method
    for(Party *party in allParties){
            if(!party.alreadyAdded){
                CLLocationCoordinate2D location = [party getPartylocation];
                NSString *partyTitle = [party getPartyName];
                MKAnnotationView *partyPin = [self returnPointView:location andTitle:partyTitle andColor:MKPinAnnotationColorGreen];
                [self.map addAnnotation:partyPin.annotation];
                NSLog(@"Adding Successful!");
                party.alreadyAdded = YES;
            }

        }

Answer 1

You have to conform to the MKMapViewDelegate protocol in the header of your ViewController.

@interface mapViewController : UIViewController <MKMapViewDelegate>
@end

Then, in the implementation you have to write the method :

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

That is called each time an annotation is drawn. It's here that you should call your method, not only when adding the annotation.

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

    MKAnnotationView *pinView = [self returnPointView:annotation.coordinate andTitle:annotation.title andColor:MKPinAnnotationColorGreen];

    return pinView;
}

Finally, set the ViewController as its UIMapView delegate delegate in viewDidLoad :

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    [self.mapView setDelegate:self];
}

I suggest you have a look at the MapCallouts example project in Xcode, it's clear and simple.

Just as well, you should use dequeueReusableAnnotationViewWithIdentifier in order to be more memory efficient (as does the example).