create data model for JSON - IOS/Objective-C - ios

Question

I'm developing an IOS application in Objective C, in which i'l call a URL to retrieve an array JSON objects (restaurants). I want to parse them onto a objective-C Model. Using them to populate on to a UICollectionView that i have already designed. My task requires me to design this model to store the Json objects and then use them to populate onto UICollectionView. I don't know how to achieve this in Objective-C, please help me on this. The JSON retrieved is as follows.
"restaurants" : [
{
"name": "Burger Bar",
"backgroundImageURL": "http://somthing.com/Images/1.png",
"category" : "Burgers",
"contact": {
"phone": "1231231231",
"formattedPhone": "[phone]",
"twitter": "1twitter"
},
"location": {
"address": "5100 Belt Line Road, STE 502",
"crossStreet": "Dallas North Tollway",
"lat": 32.950787,
"lng": -96.821118,
"postalCode": "75254",
"cc": "US",
"city": "Addison",
"state": "TX",
"country": "United States",
"formattedAddress": [
"5100 Belt Line Road, STE 502 (Dallas North Tollway)",
"Addison, TX 75254",
"United States"
]
}
},
{
"name": "seafood Kitchen",
"backgroundImageURL": "http://somthing.com/Images/2.png",
"category": "Seafood",
"contact": {
"phone": "3213213213",
"formattedPhone": "[phone]",
"twitter": "2twitter"
},
"location": {
"address": "18349 Dallas Pkwy",
"crossStreet": "at Frankford Rd.",
"lat": 32.99908456526653,
"lng": -96.83018780592823,
"postalCode": "33331",
"cc": "US",
"city": "Dallas",
"state": "TX",
"country": "United States",
"formattedAddress": [
"18349 Dallas Pkwy (at Frankford Rd.)",
"Dallas, TX 75287",
"United States"
]
}
}
]
Below code shows how to call URL and retrieve and print the parse JSON objects.
NSString *urlString = #"http://somthing.com/Images/collection.json";
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (!error) {
NSError* parseError;
id parse = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&parseError];
NSLog(#"%#", parse);
}
}];
How to create the restaurant data model. Or is there any other way to go about this?

Answer 1

There's no need for any external library whatsoever. Look at the data that you get, and it's obvious that you want a class each representing a contact, a location, a restaurant, and you want to translate the JSON response into an array of restaurants. It's obvious what properties the contact, location and restaurant should have.
For each of the classes, you don't want the init method at all, so declare an init method with flags that make its use illegal. For each class, declare a method initWithJSONDictionary:(NSDictionary*)dict which takes the appropriate dictionary as an argument, extracts all the properties from the dictionary, logs if the values are not what you expect and returns nil if the data is faulty.
Use NSJSONSerialization to parse the complete JSON data, check that it's an array and each array element is a dictionary, and call [[MyRestaurant alloc] initWithJSONDictionary:...] for each dictionary.
That's absolutely straightforward, and for something simple like your case it should take you an hour or two to write bullet proof code for this.

Answer 2

You could use Json2Model from here https://github.com/fredlo2010/Json2Model
It would generate 4 object for you:
Restaurants.h
Restaurant.h
Contact.h
Location.h
Here is an example of Contact.h and Contact.n
#import <Foundation/Foundation.h>
#interface Contact : NSObject
#property (strong, nonatomic) NSString *twitter;
#property (strong, nonatomic) NSString *phone;
#property (strong, nonatomic) NSString *formattedPhone;
- (instancetype) initWithTwitter: (NSString *)twitter andPhone: (NSString *)phone andFormattedPhone: (NSString *)formattedPhone;
#end
#import "Contact.h"
#implementation Contact
- (instancetype) initWithTwitter: (NSString *)twitter andPhone: (NSString *)phone andFormattedPhone: (NSString *)formattedPhone {
self = [super init];
if (self) {
self.twitter = twitter;
self.phone = phone;
self.formattedPhone = formattedPhone;
}
return self;
}
#end

Answer 3

Use JSONModel https://github.com/icanzilb/JSONModel
.h file
#import "JSONModel.h"
#interface location : JSONModel
{
}
#property (nonatomic,strong) NSString *address;
#property (nonatomic,strong) NSString *crossStreet;
#property (nonatomic,strong) NSString *lat;
#property (nonatomic,strong) NSString *lng;
#property (nonatomic,strong) NSString *postalCode;
#property (nonatomic,strong) NSString *cc;
#property (nonatomic,strong) NSString *city;
#property (nonatomic,strong) NSString *state;
#property (nonatomic,strong) NSString *country;
#property (nonatomic,strong) NSArray *formattedAddress;
#end
#interface contact:JSONModel
{
}
#property (nonatomic,strong) NSString *phone;
#property (nonatomic,strong) NSString *formattedPhone;
#property (nonatomic,strong) NSString *twitter;
#end
#interface Restaurant : JSONModel
#property (nonatomic,strong) location *objectLocation;
#property (nonatomic,strong) contact *objContact;
#property (nonatomic,strong) NSString *name;
#property (nonatomic,strong) NSString *backgroundImageURL;
#property (nonatomic,strong) NSString *category;
#end
.m file
#implementation Restaurant
-(id)init{
self = [super init];
if (self) {
_category = #"";
_name = #"";
_backgroundImageURL = #"";
}
return self;
}
#end
#implementation contact
-(id)init{
self = [super init];
if (self) {
_phone = #"";
_formattedPhone = #"";
_twitter = #"";
}
return self;
}
#end
#implementation location
-(id)init{
self = [super init];
if (self) {
_address = #"";
_crossStreet = #"";
_lat = #"";
_lng= #"";
_postalCode = #"";
_city = #"";
_state = #"";
_cc = #"";
_country = #"";
}
return self;
}
//objects is the response object
NSArray* models = [Restaurant arrayOfModelsFromDictionaries: objects];

Answer 4

Store the array of restaurants from json in your model object and then you can retrieve the data required for your collection view from model so that all parsing stuff will remain in your model.
.h
#interface Model : NSObject
#property(nonatomic,strong)NSArray *restaurants;
#end
.m
#implementation Model
-(NSIteger)getRestaurantsCount{
return restaurants.count;
}
//getRestaurantAtIndex:
//getRestaurantNameAtIndex:
#end

Answer 5

Looking at the example JSON, you are getting an array of restaurants according to the [ ] brackets. You can retrieve the array with this:
NSArray *restArray= [parse objectForKey:#"restaurants"];
Now you want to loop through that array and parse the structure like the following:
for (NSDictionary *restaurant in restArray){
NSString* name = [restaurant objectForKey:#"name"];
NSDictionary* location = [restaurant objectForKey:"location"];
//etc...
}

Answer 6

You can parse the data you get in your callback to NSDictionary object:
NSData *response = someData; // data you are getting in callback
NSError *error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:response options:kNilOptions error:&error];
NSArray *restaurants = [json objectForKey:#"restaurants"];

Answer 7

Checkout this repo, it also comes with easy coredata integration
https://github.com/BadChoice/daikiri