Question

I am coding multiple annotations into a project. Currently I have 30 annotations, and growing. I’m wondering if there is a simplier way of having to create a annotation.h and annotation.m classes for each single annotation.

Currently in my map view controller, I create the annotation objects and place them in an array, which has been working well for me but as you could imagine, its a lot of code to manage once you have tons of annotations, not to mention tons of classes.

So for example, one of the annotation classes looks like this:

Annotation.h:

//Annotation.h

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface Annotation : NSObject {

}

@end

Annotation.m:

//Annotation.m

#import "Annotation.h"

@implementation Annotation

-(CLLocationCoordinate2D)coordinate;
{
    CLLocationCoordinate2D theCoordinate;
    theCoordinate.latitude = -45.866416;
    theCoordinate.longitude = 170.519931;
    return theCoordinate; 
}

-(NSString *)title
{
    return @"Title";
}

-(NSString *)subtitle
{
    return @"Subtitle";
}

-(void)dealloc
{
    [super dealloc];
}

@end

I’m thinking of reading in a CSV file with all the annotations would be the best way to go, any option I choose will result in me rewriting a lot of code, which is why I’m asking this question before I do anything. Does anyone have any suggestions?

Answer 1

The MapCallouts sample app unfortunately doesn’t give a good example of how to implement a generic annotation class.

Your class that implements the MKAnnotation protocol can provide a settable coordinate property or a custom init method that takes the coordinates.

However, since you’re using iOS 4.0, an easier option is to just use the pre-defined MKPointAnnotation class that provides properties that you can set. For example:

MKPointAnnotation *annot = [[MKPointAnnotation alloc] init];
annot.title = @"Title";
annot.subtitle = @"Subtitle";
annot.coordinate = CLLocationCoordinate2DMake(-45.866416, 170.519931);
[mapView addAnnotation:annot];
[annot release];

The annotation data can of course come from anywhere and you can loop through the data to create the annotations on the map.