JSON parsing: show data on UITableView - ios

Question

This is the given API that I have to parse.I also have to show the name on my UITableView. I want to fetch the value of name n show it on table view.
This is the code:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [ episodes count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *simpleTableIdentifier = #"SimpleTableItem";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
}
cell.textLabel.text = [[ episodes objectAtIndex:indexPath.row] objectForKey:#"names"];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UIAlertView *logoutConfirm = [[UIAlertView alloc]initWithTitle:#"Toilet Finder" message:#"" delegate:self cancelButtonTitle:nil otherButtonTitles:#"Display on Map",#"Route",#"Cancel", nil];
logoutConfirm.tag = 111;
[logoutConfirm show];
}
- (void) parseJSONWithURL:(NSURL *) jsonURL
{
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
dispatch_async(queue, ^{
NSError *error = nil;
NSString *json = [NSString stringWithContentsOfURL:jsonURL
encoding:NSASCIIStringEncoding error:&error];
if (error == nil){
WebInServe=#"http://api.kivaws.org/v1/loans/search.json?status=fundraising";
NSLog(#"URL %#", WebInServe);
NSURL *Final_Url = [NSURL URLWithString:WebInServe];
NSData* jsonData = [NSData dataWithContentsOfURL: Final_Url];
NSError* error;
jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];
NSLog(#"What is contain let me check %#",jsonDict);
NSArray* latestLoans = [jsonDict objectForKey:#"loans"];
NSLog(#"loans in array: %#", latestLoans);
episodes = [[jsonDict valueForKey:#"latestLoans"]valueForKey:#"name"];
if (error == nil)
{
dispatch_async(dispatch_get_main_queue(), ^{
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
episodes = [[jsonDict valueForKey:#"latestLoans"]valueForKey:#"name"];
[tableView reloadData];
});
}
I have tried using:
episodes = [[jsonDict valueForKey:#"latestLoans"]objectForKey:#"name"];
I have used several tymes objectForKey and valueForkey but in the above code and in the
cell.textLabel.text = [[ episodes objectAtIndex:indexPath.row] objectForKey:#"names"];
line of code in cellForRowAtIndexPath: method
but the data is not displayed on tableview...indeed it is displayed on NSLog...

Answer 1

Why using dispatch_queues instead of using the dedicated async API of NSURLConnection?
As explained in Apple's Concurrency Programming Guide, when there already is a dedicated API to execute some task in a concurrent manner, avoid to make your own concurrent version by wrapping a synchronous call (like +[NSString stringWithContentOfURL:] in your case) inside asynchronous queues (like dispatch_async on a concurrent queue in your case).
Moreover, your latestLoans variable (which you then NSLog) extracts its content from a key called #"loans", but in the next line when you try to extract the episodes, you extract it from the dictionary assumed to be associated to a #"latestLoans" key. There is probably some discrepancy in your code there, isn't it? That's probably your main problem in your code.
And finally sometimes you use valueForKey: (which is a generic Key-Value-Coding method that works using introspection, not at all a dedicated NSDictionary-specific method) instead of objectForKey: (which is what you need to use when accessing objects from an NSDictionary).
Sure valueForKey: will work but objectForKey: being the dedicated method for NSDictionary it will be more efficient.
Personally I even prefer the new "Objective-C Modern notation" for Object Literals, namely dict[key] that the compiler will translate to objectForKey: automatically for you (this [] notation is only some syntaxic sugar to be more concise)
So here comes my code suggestion:
...
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse* resp, NSData* jsonData, NSError* err) {
...
NSDictionary* jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];
NSArray* latestLoans = jsonDict[#"loans"];
self.episodes = latestLoans[#"name"];
[self.tableView reloadData];
}];

Answer 2

It seems the problem is here:
episodes = [[jsonDict valueForKey:#"latestLoans"]valueForKey:#"name"];
The root of the JSON response has only two items - "paging" and "loans". You are asking for "latestLoans". Since there is no such item in the root level of the JSON, you will get nil in episodes.
I think you should use the call you performed for the logging:
NSArray* latestLoans = [jsonDict objectForKey:#"loans"];
Try with
episodes = [jsonDict objectForKey:#"loans"];
instead of
episodes = [[jsonDict valueForKey:#"latestLoans"]valueForKey:#"name"];