How do I gather JSON data nested in an array using NSDictionary - ios

Question

I have the following JSON:
{
0: 200,
error: false,
campaigns: {
current_campaigns: [
{
id: "1150",
campaign_type_id: "1",
campaign_type: "Type",
title: "Name (with type) ",
url: "http://www.example.com",
special: null,
campaign_instructions: "Here's what you do",
pay_description: "",
start: "2013-10-14 00:00:00",
end: "2014-03-31 23:59:59"
},
{
id: "1151",
campaign_type_id: "1",
campaign_type: "Type",
title: "Name (with type) ",
url: "http://www.example.com",
special: null,
campaign_instructions: "Here's what you do",
pay_description: "",
start: "2013-10-14 00:00:00",
end: "2014-03-31 23:59:59"
},
],
new_campaigns: [
{
id: "1152",
campaign_type_id: "1",
campaign_type: "Type",
title: "Name (with type) ",
url: "http://www.example.com",
special: null,
campaign_instructions: "Here's what you do",
pay_description: "",
start: "2013-10-14 00:00:00",
end: "2014-03-31 23:59:59"
}
]
}
And the following code
NSURL *theJSON = [NSURL URLWithString:#"http://somejsonurl"];
NSURLRequest *request = [NSURLRequest requestWithURL:theJSON];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError){
NSError *errorJson = nil;
NSDictionary *dataDictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:&errorJson];
NSArray *campaigns = dataDictionary[#"campaigns"];
for (NSDictionary *campaignList in campaigns) {
NSLog(#"Call gave: %#", campaigns);
}
How would I end up logging the current_campaign title?
I tried
NSLog(#"%#", [campaignList objectForKey:#"title"]);
NSLog(#"%#", campaigns[#"title"] );
and no success. I'm fairly new at Objective C and am having trouble understanding how you dig into JSON with NSArray and NSDictionary. Any help would be greatly appreciated!

Answer 1

The easiest thing to remember about JSON is that every time you see a bracket "[", that means the beginning of an Array and "]" is the end. Every time you see a curly brace "{" that means the beginning of a Dictionary and "}" is the end.
So in your example, campaigns is a Dictionary element with another Dictionary (current_campaigns) that contains an Array of Dictionaries. Each of those Dictionaries has a key called title.
So the long version (untested):
NSDictionary *campaigns = [dataDictionary objectForKey:#"campaigns"];
NSArray *currentCampaigns = [campaigns objectForKey:#"current_campaigns"];
for (NSDictionary *thisCampaign in currentCampaigns) {
NSLog(#"title: %#", [thisCampaign objectForKey:#"title"]);
}