This article comes as a completion to my previous ones, XCode : using MapKit with no geocoding available out of the box and XCode: Modal windows – Google maps and shows how to add pins on your already created Map View.

First of all, adding the points to the map is not as intuitive as it might seem, so let’s start by creating a new class called POI – point of interest. Its header must be filled with this code:

#import <foundation foundation.h>
#import <mapkit mapkit.h>
#import <corelocation corelocation.h>

@interface POI : NSObject  {    CLLocationCoordinate2D coordinate;        NSString *subtitle;         NSString *title;     }

@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;@property (nonatomic,retain) NSString *subtitle;@property (nonatomic,retain) NSString *title;- (id) initWithCoords:(CLLocationCoordinate2D) coords;

@end

(more…)

While working on the CSCW Lab project, I encountered a situation in which the XML-RPC call returned an image, of course encoded as Base64. And guess what – in its known style, Apple doesn’t provide Base64 encoding and decoding – quite lame, given the fact that this encoding is used everywhere in data transfer over the internet – e-mail, browsers, web services – all of them use at some point this encoding to overcome the different local encodings on each one’s machine.

Once identified this problem, I had to solve it somehow – but guess what? – over the free sources there aren’t too many functions that provide this simple and basic encoding.

Finally, after few hours of searching, I finally found that Eric Czarny had a very successful implementation of this in its Cocoa XML-RPC Framework . After taking a quick look at its code, I end up using and importing into my project the

• NSStringAdditions.h. NSStringAdditions.m – providing the new category

+ (NSString *)base64StringFromData: (NSData *)data length: (int)length;

• NSDataAdditions.h and NSDataAdditions providing the new category:

+ (NSData *)base64DataFromString: (NSString *)string;

Being categories, they are automatically added to NSString and NSData automatically at runtime, thus their usage is straight forward :

UIImageView *uiIV;
// currentElementValue holds the string representation of the image, encoded in Base64
NSData *nsD = [NSData base64DataFromString: [dataLayer currentElementValue]];

if ([nsD ){
    uiIV = [[UIImageView alloc] initWithImage:[UIImage imageWithData: nsD]];
}