Parsing JSON with AFHTTPClient - objective-c

Question

I'm using the AFNetworking library to parse json using the AFHTTPClient. I can verify that the json is being parsed within the client block and send that data to my json model. However, when I try to access the json model from outside the block I get no data. How can I pass the parsed json data to the json model then access that model data elsewhere in the app?
the AFHTTPClient subclass / singleton:
#import <Foundation/Foundation.h>
#import "AFHTTPClient.h"
#interface JsonClient : AFHTTPClient
+ (JsonClient *)sharedClient;
#end
#import "JsonClient.h"
#import "AFJSONRequestOperation.h"
static NSString *const kJsonBaseURLString = #"https://alpha-api.app.net/";
#implementation JsonClient
+ (JsonClient *)sharedClient {
static JsonClient *_sharedClient = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_sharedClient = [[JsonClient alloc] initWithBaseURL:[NSURL URLWithString:kJsonBaseURLString]];
});
return _sharedClient;
}
- (id)initWithBaseURL:(NSURL *)url {
self = [super initWithBaseURL:url];
if (!self) {
return nil;
}
[self registerHTTPOperationClass:[AFJSONRequestOperation class]];
[self setDefaultHeader:#"Accept" value:#"application/json"];
return self;
}
#end
the JSON model data:
#import <Foundation/Foundation.h>
#interface TheJson : NSObject
#property (nonatomic, copy) NSString *createdAt;
#property (nonatomic, copy) NSString *userText;
- (id)initWithDictionary:(NSDictionary *)dict;
#end
#import "TheJson.h"
#implementation TheJson
- (id)initWithDictionary:(NSDictionary *)dict {
self = [super init];
if (self) {
self.createdAt = [dict objectForKey:#"created_at"];
self.userText = [dict objectForKey:#"text"];
}
return self;
}
#end
the ViewController to update the user interface:
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
#end
#import "ViewController.h"
#import "JsonClient.h"
#import "TheJson.h"
#interface ViewController ()
#property (weak) IBOutlet UILabel *createdLabel;
#property (weak) IBOutlet UILabel *textLabel;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (IBAction)fetchJsonData:(id)sender {
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
[[JsonClient sharedClient] getPath:#"stream/0/posts/stream/global" parameters:nil
success:^(AFHTTPRequestOperation *operation, id JSON) {
NSArray *postsFromResponse = [JSON valueForKeyPath:#"data"];
NSDictionary *dictFromArray = postsFromResponse[0];
TheJson *jsonObject = [[TheJson alloc] initWithDictionary:dictFromArray];
NSLog(#"createdAt is %#", jsonObject.createdAt);
NSLog(#"text from user is %#", jsonObject.userText);
[self updateInterface];
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error is %#", [error description]);
}
];
}
- (void)updateInterface {
TheJson *thejson;
[_createdLabel setText:thejson.createdAt];
[_textLabel setText:thejson.userText];
}
#end

Answer 1

You haven't passed the new jsonObject out of the block nor stored it anywhere. A short term answer is to declare updateInterface to take the jsonObject as a parameter.
So your updateInterface becomes updateInterface: something like this:
- (void)updateInterface:(TheJson*)thejson {
[_createdLabel setText:thejson.createdAt];
[_textLabel setText:thejson.userText];
}
...and then within your block, you call this method like this:
[self updateInterface:jsonObject];
Longer term, if your app has many of these objects and/or needs to hold onto them for any amount of time, you probably want to think about how you will store and organize these as you download them.