iOS Basic Request to webservice - ios

Question

Can anyone point me in the right direction of a good tutorial or possibly answer this question.
I have some JSON to be returned on my web server
{
first_name: "Joe";
last_name: "Smith";
department: "Human Resources";
}
How do I make a http request to get this information at the click of a button and display as text on the iphone.?
Complete newbie so please 'dumb' down.

Answer 1

create a jsonviewcontroller class
#import <UIKit/UIKit.h>
#interface JSONViewController : UIViewController<UITableViewDelegate,UITableViewDataSource,NSURLConnectionDataDelegate>
{
NSString *label;
}
#property (weak, nonatomic) IBOutlet UITableView *myTableView;
- (IBAction)getTop10AlbumAction:(id)sender;
#end
then in implementation class:-
#import "JSONViewController.h"
#interface JSONViewController ()
{
NSMutableData *webData;
NSURLConnection *connection;
NSMutableArray *array;
NSString *category;
}
#end
#implementation JSONViewController
- (void)viewDidLoad
{
[super viewDidLoad];
array=[[NSMutableArray alloc]init];
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[webData setLength:0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[webData appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(#"Failed with Error");
}
this is the place where actual parsing happens, we fetch the title of albums from respective dictionary and arrays. to understand this first go to this link http://jsonviewer.stack.hu/#http://itunes.apple.com/us/rss/topalbums/limit=10/json this is the json viewer which shows the structure of the content that we are going to access. dont panic! its really easy if u try parsing some json urls
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSDictionary *allDataDictionary=[NSJSONSerialization JSONObjectWithData:webData options:0 error:nil];
NSDictionary *feed=[allDataDictionary objectForKey:#"feed"];
NSArray *arrayOfEntry=[feed objectForKey:#"entry"];
for (NSDictionary *dict in arrayOfEntry) {
NSDictionary *title=[dict objectForKey:#"title"];
NSString *label=[title objectForKey:#"label"];
[array addObject:label];
}
[[self myTableView]reloadData];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return[array count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier=#"cell";
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
//clear background color
[[cell textLabel] setBackgroundColor:[UIColor clearColor]];
[[cell detailTextLabel] setBackgroundColor:[UIColor clearColor]];
//set cell text
cell.textLabel.text=[array objectAtIndex:indexPath.row];
//set cell accessory type
cell.accessoryType=UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
here we specify the itunes url that we are going to parse and make connection request
- (IBAction)getTop10AlbumAction:(id)sender {
NSURL *url=[NSURL URLWithString:#"http://itunes.apple.com/us/rss/topalbums/limit=10/json"];
NSURLRequest *request=[NSURLRequest requestWithURL:url];
connection=[NSURLConnection connectionWithRequest:request delegate:self];
if (connection) {
webData=[[NSMutableData alloc]init];
}
[[self myTableView]reloadData];
}
#end
i hope i have made it clear enough!

Answer 2

I suggest you two different tutorials:
Creating a simple interface. Here is a sample from Apple that have a button and a text displayed: iOS Button - Label sample
Insert into controller code (i.e. changeGreeting:) the code that calls the webservice: iOS JSON Webservice tutorial