MapKit custom pin annotation - ios

Question

I have the following files:
annotation.h:
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>
#interface annotation : NSObject <MKAnnotation>
#property(nonatomic, assign) CLLocationCoordinate2D coordinate;
#property(nonatomic, copy) NSString *title;
#property(nonatomic, copy) NSString *subtitle;
#end
annotation.m:
#import "annotation.h"
#implementation annotation
#synthesize coordinate, title, subtitle;
#end
And in the main code, which takes in an NSURL found elsewhere:
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[spinner stopAnimating];
// json parsing
results = [NSJSONSerialization JSONObjectWithData:data options:nil error:nil];
NSMutableArray * locations = [[NSMutableArray alloc] init];
CLLocationCoordinate2D location;
annotation * myAnn;
NSArray *pins = mapView.annotations;
if ([pins count])
{
[mapView removeAnnotations:pins];
}
/* loop through the array, each key in the array has a JSON String with format:
* title <- string
* strap <- string
* id <- int
* date <- date
* lat <- floating point double
* long <- floating point double
* link <- string
*/
int i;
for (i = 0; i < [results count]; i++) {
//NSLog(#"Result: %i = %#", i, results[i]);
//NSLog(#"%#",[[results objectAtIndex:i] objectForKey:#"long"]);
myAnn = [[annotation alloc] init];
location.latitude = (double)[[[results objectAtIndex:i] objectForKey:#"lat"] doubleValue];
location.longitude = (double)[[[results objectAtIndex:i] objectForKey:#"long"] doubleValue];
myAnn.coordinate = location;
myAnn.title = [[results objectAtIndex:i] objectForKey:#"title"];
myAnn.subtitle = [[results objectAtIndex:i] objectForKey:#"strap"];
[locations addObject:myAnn];
//NSLog(#"%i", [[results objectAtIndex:i] objectForKey:#"lat"]);
}
[self.mapView addAnnotations:locations];
Previous things I have looked at for this say that I need to use MKAnnotationView as opposed to MKPinAnnotationView but as you can see I do not use either, is it possible for me to use custom images for the pins that are dropped on the screen.

Answer 1

You (a) make sure to define your view controller to be the delegate for your MKMapView; and (b) implement viewForAnnotation, e.g.:
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
if ([annotation isKindOfClass:[MKUserLocation class]]) {
return nil;
}
if ([annotation isKindOfClass:[CustomAnnotation class]]) {
static NSString * const identifier = #"MyCustomAnnotation";
MKAnnotationView* annotationView = [mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (annotationView) {
annotationView.annotation = annotation;
} else {
annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation
reuseIdentifier:identifier];
}
// set your annotationView properties
annotationView.image = [UIImage imageNamed:#"Your image here"];
annotationView.canShowCallout = YES;
// if you add QuartzCore to your project, you can set shadows for your image, too
//
// [annotationView.layer setShadowColor:[UIColor blackColor].CGColor];
// [annotationView.layer setShadowOpacity:1.0f];
// [annotationView.layer setShadowRadius:5.0f];
// [annotationView.layer setShadowOffset:CGSizeMake(0, 0)];
// [annotationView setBackgroundColor:[UIColor whiteColor]];
return annotationView;
}
return nil;
}
By the way, in my example above, I changed the name of your annotation class to CustomAnnotation. annotation is a horrible name for a class because (a) it doesn't follow class naming conventions of upper case first letter; and (b) it's identical to the variable name, annotation, that many MKMapViewDelegate methods will use by default.
References
Location Awareness Programming Guide
Map Kit Framework Reference

Answer 2

You can certainly use custom images for an MKAnnotationView, see iOS MapKit custom pins.

Answer 3

Both MKAnnotationPinView and MKAnnotationView are subclasses of UIView and therefore will allow custom views.