问如何使用MKAnnotation

EN

@interface  AdoptingAnAnnotation: NSObject {
}

@synthesize latitude; 
@synthesize longitude;

@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
- (NSString *) title;
- (NSString *) subtitle;
@end

#import "AdoptingAnAnnotation.h"

@implementation AdoptingAnAnnotation

@synthesize latitude;
@synthesize longitude;

- (id) initWithLatitude:(CLLocationDegrees) lat longitude:(CLLocationDegrees) lng {
    latitude = lat;
    longitude = lng;
    return self;
   }
- (CLLocationCoordinate2D) coordinate {
    CLLocationCoordinate2D coord = {self.latitude, self.longitude};
    return coord;
    }
- (NSString *) title {
    return @"217 2nd St";
    }
- (NSString *) subtitle {
    return @"San Francisco CA 94105";
    }
@end