download image

- (void)fifthAttempt {
    // Create the request.
    NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://upload.wikimedia.org/wikipedia/commons/4/47/PNG_transparency_demonstration_1.png"]
                                              cachePolicy:NSURLRequestUseProtocolCachePolicy
                                          timeoutInterval:60.0];

    // Create the NSMutableData to hold the received data.
    // receivedData is an instance variable declared elsewhere.
    receivedData = [NSMutableData dataWithCapacity: 0];

    // create the connection with the request
    // and start loading the data
    NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
    if (!theConnection) {
        // Release the receivedData object.
        receivedData = nil;

        // Inform the user that the connection failed.
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    // Append the new data to receivedData.
    // receivedData is an instance variable declared elsewhere.
    [receivedData appendData:data];
}


- (void)connection:(NSURLConnection *)connection
  didFailWithError:(NSError *)error
{
    // Release the connection and the data object
    // by setting the properties (declared elsewhere)
    // to nil.  Note that a real-world app usually
    // requires the delegate to manage more than one
    // connection at a time, so these lines would
    // typically be replaced by code to iterate through
    // whatever data structures you are using.
    theConnection = nil;
    receivedData = nil;

    // inform the user
    NSLog(@"Connection failed! Error - %@ %@",
          [error localizedDescription],
          [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    // do something with the data
    // receivedData is declared as a property elsewhere
    NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);

    // Release the connection and the data object
    // by setting the properties (declared elsewhere)
    // to nil.  Note that a real-world app usually
    // requires the delegate to manage more than one
    // connection at a time, so these lines would
    // typically be replaced by code to iterate through
    // whatever data structures you are using.
    theConnection = nil;
    receivedData = nil;
}