Parsing YouTube JSON - ios

Question

I'm having trouble parsing JSON from YouTube. I'm trying to get the title, videoId, and default thumbnail URL. I've parsed JSON before but I'm having issues getting what I want from this.
Here is my code. It's crashing with an unrecognized selector error on NSDictionary* snippet = [item objectForKey:#"snippet"]; The error is -[__NSCFString objectForKey:]: unrecognized selector sent to instance 0x108781b0
#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
#define storeURL [NSURL URLWithString: #"https://www.googleapis.com/youtube/v3/playlistItems?part=snippet&maxResults=25&playlistId=UUkfYL7q5G8CYtZgtSAwmwzw&key=AIzaSyBS4do208_KPGHAhszfVkHadSvtfSgr7Mo"]
#import "KFBYoutubeVideosTableViewController.h"
#import "SVProgressHUD.h"
#import "Reachability.h"
#import "TSMessage.h"
#import "TSMessageView.h"
#interface KFBYoutubeVideosTableViewController ()
#end
#implementation KFBYoutubeVideosTableViewController
#synthesize title, videoID, thumbURL, url, titleArray, videoIDArray, thumbArray;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[[SVProgressHUD appearance]setHudBackgroundColor:[UIColor blackColor]];
[[SVProgressHUD appearance]setHudForegroundColor:[UIColor whiteColor]];
[SVProgressHUD showWithStatus:#"Loading"];
Reachability *networkReachability = [Reachability reachabilityForInternetConnection];
NetworkStatus networkStatus = [networkReachability currentReachabilityStatus];
if(networkStatus == NotReachable)
{
[TSMessage showNotificationWithTitle:#"Network Error" subtitle:#"No active network connection!" type:TSMessageNotificationTypeError];
[SVProgressHUD dismiss];
}
self.title = #"KFB Videos";
self.tableView = [[UITableView alloc]initWithFrame:CGRectZero style:UITableViewStyleGrouped];
self.tableView.backgroundColor = [UIColor darkGrayColor];
url = [NSURL URLWithString:#"https://www.googleapis.com/youtube/v3/playlistItems?part=snippet&maxResults=25&playlistId=UUkfYL7q5G8CYtZgtSAwmwzw&key=AIzaSyBS4do208_KPGHAhszfVkHadSvtfSgr7Mo"];
dispatch_async(kBgQueue, ^{
NSData *data = [NSData dataWithContentsOfURL:url];
if (data == nil)
{
NSLog(#"data is nil");
}
else
{
[self performSelectorOnMainThread:#selector(fetchedData:) withObject:data waitUntilDone:YES];
}
});
}
- (void)viewDidDisappear:(BOOL)animated
{
[SVProgressHUD dismiss];
}
- (void)fetchedData:(NSData *)responseData
{
NSError *error;
titleArray = [[NSMutableArray alloc]init];
videoIDArray = [[NSMutableArray alloc]init];
thumbArray = [[NSMutableArray alloc]init];
NSArray *json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSLog(#"%#", json);
for (NSDictionary *item in json)
{
NSDictionary* snippet = [item objectForKey:#"snippet"];
title = [snippet objectForKey:#"title"];
videoID = [[snippet objectForKey:#"resourceId"] objectForKey:#"videoID"];
thumbURL = [[[snippet objectForKey:#"thumbnails"] objectForKey:#"default"] objectForKey:#"url"];
[titleArray addObject:title];
[videoIDArray addObject:videoID];
[thumbArray addObject:thumbURL];
}
[self.tableView reloadData];
[SVProgressHUD dismiss];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [titleArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell == nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"Cell"];
cell.textLabel.font = [UIFont systemFontOfSize:16.0];
}
if (cell)
{
cell.backgroundColor = [UIColor clearColor];
cell.textLabel.text = [titleArray objectAtIndex:indexPath.row];
cell.textLabel.textColor = [UIColor blackColor];
}
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Title: %#, Video ID: %#, Thumbnail URL: %#", [titleArray objectAtIndex:indexPath.row],[videoIDArray objectAtIndex:indexPath.row], [thumbArray objectAtIndex:indexPath.row]);
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
Here is the JSON:
{
etag = "\"bvxF-DWHx1toJotsdJBeCm43SLs/tyIRY5zDT7R6YEirBFeFh0tVLCw\"";
items = (
{
etag = "\"bvxF-DWHx1toJotsdJBeCm43SLs/ON_wGC8nyy0H_bqRqQHlA7mXiM0\"";
id = UUstIg9nSlWxTaKpWq7G0sppJf9oH5NaDE;
kind = "youtube#playlistItem";
snippet = {
channelId = UCkfYL7q5G8CYtZgtSAwmwzw;
channelTitle = "Kentucky Farm Bureau";
description = "Celebrate June as National Dairy Month with a visit to Jericho Acres Dairy Farm in Henry County.";
playlistId = UUkfYL7q5G8CYtZgtSAwmwzw;
position = 0;
publishedAt = "2014-05-22T12:28:03.000Z";
resourceId = {
kind = "youtube#video";
videoId = VSCr40jERks;
};
thumbnails = {
default = {
height = 90;
url = "https://i1.ytimg.com/vi/VSCr40jERks/default.jpg";
width = 120;
};
high = {
height = 360;
url = "https://i1.ytimg.com/vi/VSCr40jERks/hqdefault.jpg";
width = 480;
};
maxres = {
height = 720;
url = "https://i1.ytimg.com/vi/VSCr40jERks/maxresdefault.jpg";
width = 1280;
};
medium = {
height = 180;
url = "https://i1.ytimg.com/vi/VSCr40jERks/mqdefault.jpg";
width = 320;
};
standard = {
height = 480;
url = "https://i1.ytimg.com/vi/VSCr40jERks/sddefault.jpg";
width = 640;
};
};
title = "Kentucky Farm Bureau Reports June 2014";
};
},

Answer 1

If you look closely title is not at bottom of the json response. Everyone of those nodes is a dictionary. So to get the things you want from your code you have to do this :
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSArray *items = [json objectForKey:#"items"];
for (NSDictionary *item in json)
{
NSDictionary* snippet = [item objectForKey:#"snippet"];
title = [snippet objectForKey:#"title"];
videoID = [[snippet objectForKey:#"resourceId"] objectForKey:#"videoId"];
thumbURL = [[[snippet objectForKey:#"thumbnails"] objectForKey:#"default"] objectForKey:#"url"];
}
If you are planning to do more stuff with this data i recommend you create objects and parse the json when creating each object. so you can keep track of other properties in future. It is much cleaner then this way.