Restkit Mapping Nested Array with Forsquare

Question

I'm trying to study on using restKit to get some data from foursquare.

I'm using this tutorial.

Using this code

I try to make some different, so I try to get the data from category.

Here is foursqure's json looks like

   {
  venue: {
    id: "40a55d80f964a52020f31ee3",
    name: "Clinton St. Baking Co. & Restaurant",
    contact: {
      phone: "6466026263",
      formattedPhone: "(646) 602-6263"
    },
    location: {
      address: "4 Clinton St",
      crossStreet: "at E Houston St.",
      lat: 40.721294,
      lng: -73.983994,
      postalCode: "10002",
      city: "New York",
      state: "NY",
      country: "United States",
      cc: "US"
    },
    canonicalUrl: "https://foursquare.com/v/clinton-st-baking-co--restaurant/40a55d80f964a52020f31ee3",
    categories: [
      {
        id: "4bf58dd8d48988d143941735",
        name: "Breakfast Spot",
        pluralName: "Breakfast Spots",
        shortName: "Breakfast / Brunch",
        icon: {
          prefix: "https://foursquare.com/img/categories_v2/food/breakfast_",
          suffix: ".png"
        },
        primary: true
      },
      {
        id: "4bf58dd8d48988d16a941735",
        name: "Bakery",
        pluralName: "Bakeries",
        shortName: "Bakery",
        icon: {
          prefix: "https://foursquare.com/img/categories_v2/food/bakery_",
          suffix: ".png"
        }
      },
      {
        id: "4bf58dd8d48988d16d941735",
        name: "Café",
        pluralName: "Cafés",
        shortName: "Café",
        icon: {
          prefix: "https://foursquare.com/img/categories_v2/food/cafe_",
          suffix: ".png"
        }
      }
    ],

  }
}

and here is a part the tutorial that get stats

@interface Venue : NSObject

@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) Stats *stats;


@interface Stats : NSObject

@property (nonatomic, strong) NSNumber *checkinsCount;
@property (nonatomic, strong) NSNumber *tipCount;
@property (nonatomic, strong) NSNumber *usersCount;

mapping part

RKObjectMapping *statsMapping = [RKObjectMapping mappingForClass:[Stats class]];
    [statsMapping addAttributeMappingsFromArray:@[@"checkinsCount", @"tipCount", @"usersCount"]];
    RKRelationshipMapping *statsRelation = [RKRelationshipMapping relationshipMappingFromKeyPath:@"stats" toKeyPath:@"stats" withMapping:statsMapping];
    [venueMapping addPropertyMapping:statsRelation];

after mapping.

I can easily get data as following

NSLog(@"%i",venue.stats.checkinsCount);

and it will print the checkinsCount number

now I try to get the category data. I fix the code to get the new data.

add something like this

@interface Venue : NSObject

@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) Categories *categories;

@interface Categories : NSObject

@property (nonatomic, strong) NSString *name;
@property (nonatomic ,strong) NSString *pluralName;

add mapping like this

RKObjectMapping *categoriesMapping = [RKObjectMapping mappingForClass:[Categories class]];
    [categoriesMapping addAttributeMappingsFromDictionary:@{@"name":@"name",@"pluralName":@"pluralName"}];
    RKRelationshipMapping *cate = [RKRelationshipMapping relationshipMappingFromKeyPath:@"categories" toKeyPath:@"categories" withMapping:categoriesMapping];
    [venueMapping addPropertyMapping:cate];

now I try to get the category name

NSLog(@"%@",venue.categories.pluralName);

but it always get null

I think maybe problem which is in the data type?

There are three names and I don't know how to get all of them to print out.

Sorry, my native language isn't English, so I can't explain the situation very well.

Answer 1

In the JSON, categories is an array, so the property you're trying to map it into should be:

@property (strong, nonatomic) NSArray *categories;

You logging code then needs to change to iterate the categories:

for (Categories *category in venue.categories) {
    NSLog(@"%@", category.pluralName);
}

The class Categories has a misleading name as it isn't really a collection object (as you seem to have originally intended).