FoursquareAuthentication-cont.m

#pragma mark - Web view delegate
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {

 if([request.URL.scheme isEqualToString:@"ios-app"]){
  	 // 8. get the url and check for the access token in the callback url
		NSString *URLString = [[request URL] absoluteString];
		if ([URLString rangeOfString:@"access_token="].location != NSNotFound) {
				// 9. Store the access token in the user defaults
			NSString *accessToken = [[URLString componentsSeparatedByString:@"="] lastObject];
			NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
			[defaults setObject:accessToken forKey:@"access_token"];
			[defaults synchronize];
				// 10. dismiss the view controller 
			[self dismissViewControllerAnimated:YES completion:nil];
		}
	}
	return YES;
}