i have problem with nsuser at login

i have problem with this i want want to login with another view controller the username and password recive from webservices

and responce string return the 0 and 1

NSString *responseString = [[NSStringalloc] initWithData:returnData encoding:NSUTF8StringEncoding];

NSLog(@"responcestring%@",responseString);

if([responseString isEqualToString:false] )

{

UIAlertView *alert = [[UIAlertViewalloc] initWithTitle:@""message:@"WRONG USER"delegate:selfcancelButtonTitle:@"Ok"otherButtonTitles:nil, nil];

[alert show];

[alert release];

}

else {

[prefs setObject:@"true" forKey:@"login"];

[prefs synchronize];