segue在故事板（xcode）中不起作用？

Question

您好我正在尝试使用php登录程序。

这是我的代码：

- (IBAction)login:(id)sender
{
    if ([username.text isEqualToString:@""] || [password.text isEqualToString:@""]) {

        UIAlertView *alertsuccess = [[UIAlertView alloc] initWithTitle:@"Error"
                                                               message:@"Input Your Value"
                                                              delegate:self
                                                     cancelButtonTitle:@"OK"
                                                     otherButtonTitles:nil, nil];
        [alertsuccess show];

    }

    else {
        NSError *err;

        NSString *strURL = [NSString stringWithFormat:@"http://192.168.1.5:81/cer_app/cer_login.php?username=%@", username.text];

        NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];
        manage.commonuser = username.text;

        NSLog(@"%@", manage.commonuser);

        NSString *bb = password.text;

        NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:dataURL
                                                                  options:kNilOptions
                                                                    error:&err];


        NSMutableArray *array1 = [[NSMutableArray alloc] init];
        array1 = [jsonArray objectForKey:@"key"];

        NSLog(@"%@", array1);
        NSString *aa1 = [[array1 objectAtIndex:0]objectForKey:@"password"];
        NSString *bb1 = [[array1 objectAtIndex:0]objectForKey:@"temp_password"];

        if ([bb1 isEqualToString:@""]) {
            if ([bb isEqualToString:aa1]) {
                [self performSegueWithIdentifier:@"login" sender:self];
            }
            else {
                UIAlertView *alertsuccess = [[UIAlertView alloc] initWithTitle:@"Error"
                                                                       message:@"password wrong"
                                                                      delegate:self
                                                             cancelButtonTitle:@"OK"
                                                             otherButtonTitles:nil, nil];
                [alertsuccess show];
            }
        }
        else {
            if ([bb isEqualToString:bb1]) {
                [self performSegueWithIdentifier:@"temp_login" sender:self];
            }
        }
    }
}

在这里，我从我的php获取了arrary1值，并在控制台中显示，但我的performSegueWithIdentifier无效。