login block

- (IBAction)login:(UIButton *)sender
{
    
    NSString *userName = self.emailTextField.text;
    NSString *password = self.passwordTextField.text;
    
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    hud.labelText = @"Logging In...";
    
    TTLoginController *login = [[TTLoginController alloc] init];
    login.onLoginSuccessful = ^(TTUser *user) {
        [TTUser loginWithUsername:userName password:password block:^(TTUser *user2, NSError *error) {
            if (error) {
                [UIAlertView showAlertViewWithTitle:NSLocalizedString(@"Server Error", @"Login Error Title")
                                            message:NSLocalizedString(@"A Server error occurred.  Please try again", @"Login Error Message")
                                  cancelButtonTitle:NSLocalizedString(@"OK", @"Login Error OK Button")
                                  otherButtonTitles:nil
                                            handler:nil];
            } else {
                // Temporary fix to avoid a retain cycle.
                TTLoginController *loginAgain = [[TTLoginController alloc] init];
                loginAgain.onLoginSuccessful(user2);
            }
            [MBProgressHUD hideAllHUDsForView:self.view animated:YES];
        }];
    };
}