Why is MKMapView delegate method not being called? - objective-c

Question

I'm very new to iphone development and I'm trying to annotate a map. I've been able to get 3 location points on a map with hardcoded coordinates and now I'm trying to customize the pins. I know to do that you need to implement the:-(MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation { delegate method.
For some reason I've been unable to even get it called. Here is what I have in the controller header:
#import "ArtPiece.h"
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#interface TestViewController : UIViewController <MKMapViewDelegate> {
MKMapView *mapView;
NSMutableArray *mapAnnotations;
float results_lat[3];
float results_long[3];
NSMutableArray *results_title;
NSMutableArray *Arts;
}
#property (nonatomic, retain) IBOutlet MKMapView *mapView;
#property (nonatomic, retain) NSMutableArray *mapAnnotations;
#end
And here is what I have in the controller implementation:
- (void)viewDidLoad {
results_long[0] = -122.477989;
results_lat[0] = 37.810000;
results_long[1] = -122.480000;
results_lat[1] = 37.820000;
results_long[2] = -122.4850000;
results_lat[2] = 37.830000;
self.mapAnnotations = [[NSMutableArray alloc] initWithCapacity:3];
Arts = [[NSMutableArray alloc] initWithCapacity:3];
for(int x = 0; x<3; x++)
{
// creates an ArtPiece object and sets its lat and long
ArtPiece *a = [[ArtPiece alloc] init];
a.longitude = [NSNumber numberWithDouble:results_long[x]];
a.latitude = [NSNumber numberWithDouble:results_lat[x]];
a.title = #"please show up";
// add objects to annotation array
[self.mapAnnotations insertObject:a atIndex:x];
[a release];
}
// center screen on cali area
[self gotoLocation];
for(int x = 0; x<3; x++)
{
[mapView addAnnotations:mapAnnotations];
}
}
-(MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation {
NSLog(#"This is not printing to to console...");
MKPinAnnotationView *pinView = nil;
if(annotation != mapView.userLocation)
{
static NSString *defaultPinID = #"com.invasivecode.pin";
pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
if ( pinView == nil ) pinView = [[[MKPinAnnotationView alloc]
initWithAnnotation:annotation reuseIdentifier:defaultPinID] autorelease];
pinView.pinColor = MKPinAnnotationColorPurple;
pinView.canShowCallout = YES;
pinView.animatesDrop = YES;
}
else {
[mapView.userLocation setTitle:#"I am here"];
}
return pinView;
}
And here is the ArtPiece class implementation:
#import "TestViewController.h"
#import "ArtPiece.h"
#import <MapKit/MapKit.h>
#import <CoreData/CoreData.h>
#implementation ArtPiece
#synthesize title, artist, series, description, latitude, longitude;
- (CLLocationCoordinate2D)coordinate
{
CLLocationCoordinate2D theCoordinate;
theCoordinate.latitude = [self.latitude doubleValue];
theCoordinate.longitude = [self.longitude doubleValue];
return theCoordinate;
}
#end
It's probably something simple. Is there something wrong with my method declaration? Did I declare the delegate wrong? I can't figure it out, again, I'm very new to this objective c/delegate stuff. Thanks for any help.

Answer 1

The addAnnotations method expects an NSArray of objects that conform to the MKAnnotation protocol.
You are adding objects of type ArtPiece which don't seem to implement MKAnnotation which has a coordinate property (not latitude and longitude properties).
Update your ArtPiece class to conform to MKAnnotation (or use the pre-defined MKPointAnnotation class). But updating your custom class is a better fix.