xcode - user login from iphone to php - objective-c

Question

I have a piece of code in the .m file as below:
- (IBAction)btnLogin:(UIButton *)sender
{
NSString *strURL = [NSString stringWithFormat:#"http://www.myworkingdomain.com/fn_checkLogin2.php?name=%#&pass=%#", self.email.text, self.password.text];
// to execute php code
NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];
// to receive the returend value
NSString *strResult = [[[NSString alloc] initWithData:dataURL encoding:NSUTF8StringEncoding]autorelease];
if ([strResult isEqualToString:#"0"]) {
UIStoryboard *loginFailStoryBoard = [UIStoryboard storyboardWithName:#"loginFailStoryboard" bundle:nil];
UIViewController *initialFailLogin = [loginFailStoryBoard instantiateInitialViewController];
initialFailLogin.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:initialFailLogin animated:YES];
//NSLog(#"%#", strResult);
} else {
UIStoryboard *memberMenuBoard = [UIStoryboard storyboardWithName:#"memberMenuStoryboard" bundle:nil];
UIViewController *initialMemberMenu = [memberMenuBoard instantiateInitialViewController];
initialMemberMenu.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:initialMemberMenu animated:YES];
//NSLog(#"%#", strResult);
}
NSLog(#"%#", strResult);
}
#end
I am trying to determine if a person entered the right email and password and then to move on to the next view. I have the 'strResult' in my log and it shows that the php script it working correctly. It is now seems that the if..else statement that is not working due to the part [strResult isEqualToString:#"0"]
Can someone please advice where should I change to correct this so that when a member logins with the right password, he can go to the member view?
Thanks

Answer 1

#dan
The main thread is where all your UI elements are displayed. If you launch a connection on the main thread, your UI will become unresponsive until the connection is resolved (Unable to press buttons, unable to scroll etc...) In order to avoid that you should use another thread. There are other ways of doing it but the following code should do the trick without blocking your UI.
NSString *loginString =[NSString stringWithFormat:#"fn_checkLogin2.php?name=%#&pass=%#", self.email.text, self.password.text];
NSURL *url = [NSURL URLWithString:#"http://www.myworkingdomain.com/"];
NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url ];
[urlRequest setTimeoutInterval:30.0f];
[urlRequest setHTTPMethod:#"POST"];
[urlRequest setHTTPBody:[loginString dataUsingEncoding:NSUTF8StringEncoding]];
NSOperationQueue *queue= [[NSOperationQueue alloc] init];
[NSURLConnection sendAsynchronousRequest:urlRequest queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
if ([data length]>0 && error==nil) {
NSString *html = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"HTML = %#",html);
}
}
];
So if data is returned you can do stuff, if connection fails you can do other stuff without blocking your UI.