iOS download data from the web issues, NSURL

Need your quick advise. I am create a "Currency Converter" iPhone app to retrieve the data from google currency websites. It is work perfectly to download t开发者_运维百科he string of USD -> AUD, USD->CAD, USD->HKD, USD->HUF, USD->JPY. However, I don't why is NOT working and return NULL when try to retrieve USD->KRW and USD->ZMK. Please refer the code as below.

 -(void)loadData:(NSString*)countryName{
    self.responseData = [NSMutableData data];
        NSString *responseURL = [NSString stringWithFormat: @"http://www.google.com/ig/calculator?q=1USD=?%@", countryName];
        NSLog(@"URL:%@", responseURL);

        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:responseURL]];

        theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

 }

 - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
         [connection release];

         NSString* responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
         NSLog(@"This is the responseString %@", responseString);
             [responseString release];


 }
 - (void)viewDidLoad {
         [super viewDidLoad];
         [self loadData:@"AUD"];
         [self loadData:@"CAD"];
         [self loadData:@"HKD"];
         [self loadData:@"HUF"];
         [self loadData:@"JPY"];
         [self loadData:@"KRW"];
         [self loadData:@"ZMK"];
  }

Result from Console:

 2011-09-30 18:03:50.877 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?AUD
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?CAD
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?HKD
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?HUF
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?JPY
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?KRW
 2011-09-30 18:03:50.879 Converter[1691:f503] URL:http://www.google.com/ig/calculator?q=1USD=?ZMK
 2011-09-30 18:03:50.952 Converter[1691:f503] This is the responseString {lhs: "1 U.S. dollar",rhs: "1.02228583 Australian dollars",error: "",icc: true}
 2011-09-30 18:03:50.962 Converter[1691:f503] This is the responseString {lhs: "1 U.S. dollar",rhs: "7.79149947 Hong Kong dollars",error: "",icc: true}
 2011-09-30 18:03:50.966 Converter[1691:f503] This is the responseString {lhs: "1 U.S. dollar",rhs: "215.889465 Hungarian forints",error: "",icc: true}
 2011-09-30 18:03:50.982 Converter[1691:f503] This is the responseString {lhs: "1 U.S. dollar",rhs: "1.03910031 Canadian dollars",error: "",icc: true}
 2011-09-30 18:03:50.993 Converter[1691:f503] This is the responseString {lhs: "1 U.S. dollar",rhs: "76.5579544 Japanese yen",error: "",icc: true}
 2011-09-30 18:03:51.010 Converter[1691:f503] This is the responseString (null)
 2011-09-30 18:03:51.047 Converter[1691:f503] This is the responseString (null)

Please help and much appreciated.

You shouldn't share responseData with all the requests, since they're sent asynchronously they will all finish at a random time, and you're probably writing all received data (from all requests) in responseData. Each request should have its own resources (resourceData, theConnection).

Have a look at ASIHTTPRequest for a simple solution.