MKMapview place pin at location (long/lat)

Question

I have latitude and long values and I need to be able to drop a pin at this location.

Can anybody provide some advice on how to go about this?

Answer 1

You should:
1. add the MapKit framework to your project. 2. create a class which implements the MKAnnotation protocol.
Sample:

Annotation.h

@interface Annotation : NSObject  {
    NSString *_title;
    NSString *_subtitle;

    CLLocationCoordinate2D _coordinate;
}

// Getters and setters
- (void)setTitle:(NSString *)title;
- (void)setSubtitle:(NSString *)subtitle;

@end

Annotation.m

@implementation Annotation

#pragma mark -
#pragma mark Memory management

- (void)dealloc {
    [self setTitle:nil];
    [self setSubtitle:nil];

    [super dealloc];
}

#pragma mark -
#pragma mark Getters and setters

- (NSString *)title {
    return _title;
}

- (NSString *)subtitle {
    return _subtitle;
}

- (void)setTitle:(NSString *)title {    
    if (_title != title) {
        [_title release];
        _title = [title retain];
    }
}

- (void)setSubtitle:(NSString *)subtitle {
    if (_subtitle != subtitle) {
        [_subtitle release];
        _subtitle = [subtitle retain];
    }
}

- (CLLocationCoordinate2D)coordinate {
    return _coordinate;
}

- (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate {
    _coordinate = newCoordinate;
}

@end

2. create an instance of this class and set the lat/lon property
3. add the instance to the MKMapView object with this method:

- (void)addAnnotation:(id)annotation

4. You should set the delegate of the map and implement the following method:

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id )annotation {
    if ([annotation isKindOfClass:[MKUserLocation class]]) {
        return nil;
    }

    static NSString* ShopAnnotationIdentifier = @"shopAnnotationIdentifier";
    MKPinAnnotationView *pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:ShopAnnotationIdentifier];
    if (!pinView) {
        pinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:ShopAnnotationIdentifier] autorelease];
        pinView.pinColor = MKPinAnnotationColorRed;
        pinView.animatesDrop = YES;
    }
    return pinView;
}