This is the gist of using RestKit with iOS app

programming--ios-restkit

Venue.h
-------
@class Location;
@class Stats ;
 
@interface Venue : NSObject
 
@property (nonatomic, strong) NSString *name;
@property (nonatomic, strong) Location *location;
@property (nonatomic, strong) Stats *stats;
 
@end
 
Location.h
----------
#import <Foundation/Foundation.h>
 
@interface Location : NSObject
@property (nonatomic, strong) NSString *address;
@property (nonatomic, strong) NSString *city;
@property (nonatomic, strong) NSString *country;
@property (nonatomic, strong) NSString *crossStreet;
@property (nonatomic, strong) NSString *postalCode;
@property (nonatomic, strong) NSString *state;
@property (nonatomic, strong) NSNumber *distance;
@property (nonatomic, strong) NSNumber *lat;
@property (nonatomic, strong) NSNumber *lng;
@end
 
Stats.h
--------
@interface Stats : NSObject
@property (nonatomic, strong) NSNumber *checkins;
@property (nonatomic, strong) NSNumber *tips;
@property (nonatomic, strong) NSNumber *users;
@end
 
ViewController.m
----------------
#import <RestKit/RestKit.h>
#import "Venue.h"
#import "Location.h"
#import "Stats.h"
 
- (void)configureRestKit
{
    // initialize AFNetworking HTTPClient
    NSURL *baseURL = [NSURL URLWithString:@"https://api.foursquare.com"];
    AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:baseURL];
    
    // initialize RestKit
    RKObjectManager *objectManager = [[RKObjectManager alloc] initWithHTTPClient:client];
    
    // setup object mappings
    RKObjectMapping *venueMapping = [RKObjectMapping mappingForClass:[Venue class]];
    [venueMapping addAttributeMappingsFromArray:@[@"name"]];
    
    RKObjectMapping *statsMapping = [RKObjectMapping mappingForClass:[Stats class]];
    [statsMapping addAttributeMappingsFromDictionary:@{@"checkinsCount": @"checkins", @"tipsCount": @"tips", @"usersCount": @"users"}];
    
    [venueMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"stats" toKeyPath:@"stats" withMapping:statsMapping]];
 
    // define location object mapping
    RKObjectMapping *locationMapping = [RKObjectMapping mappingForClass:[Location class]];
    [locationMapping addAttributeMappingsFromArray:@[@"address", @"city", @"country", @"crossStreet", @"postalCode", @"state", @"distance", @"lat", @"lng"]];
    
    // define relationship mapping
    [venueMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"location" toKeyPath:@"location" withMapping:locationMapping]];
    
    // register mappings with the provider using a response descriptor
    RKResponseDescriptor *responseDescriptor =
    [RKResponseDescriptor responseDescriptorWithMapping:venueMapping
                                                 method:RKRequestMethodGET
                                            pathPattern:@"/v2/venues/search"
                                                keyPath:@"response.venues"
                                            statusCodes:[NSIndexSet indexSetWithIndex:200]];
    
    [objectManager addResponseDescriptor:responseDescriptor];
}
 
- (void)loadVenues
{
    NSString *latLon = @"37.33,-122.03"; // approximate latLon of The Mothership (a.k.a Apple headquarters)
    NSString *clientID = kCLIENTID;
    NSString *clientSecret = kCLIENTSECRET;
    
    NSDictionary *queryParams = @{@"ll" : latLon,
                                  @"client_id" : clientID,
                                  @"client_secret" : clientSecret,
                                  @"categoryId" : @"4bf58dd8d48988d1e0931735",
                                  @"v" : @"20140118"};
    
    [[RKObjectManager sharedManager] getObjectsAtPath:@"/v2/venues/search"
                                           parameters:queryParams
                                              success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
                                                  _venues = mappingResult.array;
                                                  NSLog(@"Venues: %@", _venues);
                                                  [self.tableView reloadData];
                                              }
                                              failure:^(RKObjectRequestOperation *operation, NSError *error) {
                                                  NSLog(@"What do you mean by 'there is no coffee?': %@", error);
                                              }];
}
 
- (void)viewDidLoad
{
    [super viewDidLoad];
    if(self.venueRequested == NO){
        [self configureRestKit];
        [self loadVenues];
        self.venueRequested =YES ;
    }
    
}