在 AFHTTPRequestOperation 失败时显示 UIAlertView

Question

当用户登录时 JSON 响应出错时，我试图在 AFHTTPRequestOperation 的失败块中显示 UIAlertView。我不确定为什么我的代码不起作用，但我是新手到 AFNetworking。

出于某种原因，即使出现错误，UIAlertView 也会显示成功。即使我没有在 UITextFields 中输入任何内容以进行登录。如何让 UIAlertView 在失败或错误块中显示？

错误的 JSON 响应是：

JSON: {
   code = Error;
   message = "Incorrect Username or Password!";
}

成功时 JSON 响应为：

JSON: {
   code = Success;
   message = "Login Successful!";
}

登录视图控制器：

@interface LoginSectionViewController ()

@property (strong, nonatomic) IBOutlet UIButton *loginButton;
@property (strong, nonatomic) IBOutlet UITextField *usernameTextField;
@property (strong, nonatomic) IBOutlet UITextField *passwordTextField;

@end

- (IBAction)loginAction:(id)sender {

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    NSDictionary *parameters = @{@"username": self.usernameTextField.text, @"password": self.passwordTextField.text};

  [manager POST:@"http://api.mysite.com/login.php" parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Success"
                                                    message:@"Login Successful!"
                                                   delegate:self
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
    UIAlertView *alertError = [[UIAlertView alloc] initWithTitle:@"Error"
                                                    message:@"Incorrect Username or Password!"
                                                   delegate:self
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
     [alertError show];
  }];
}

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (buttonIndex == 0) {
       [self.navigationController popToRootViewControllerAnimated:YES];
   }
}

Answer 1

success 和 failure 块用于指示请求中的基本错误（例如，请求因没有 Internet 连接而失败、响应不是 JSON 和解析失败等）。但它并没有查看 JSON 内容本身。

这取决于你。在您的 success 块中（即“成功接收 JSON 响应”），您可以检查 JSON 的内容以向用户指示登录是否成功。

---

我没有对此进行测试，但希望这能说明这个想法：

[manager POST:@"http://api.mysite.com/login.php" parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);

    NSDictionary *responseDictionary = responseObject;

    if ([responseDictionary[@"code"] isEqualToString:@"Success"]) {

        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Success"
                                                        message:@"Login Successful!"
                                                       delegate:self
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
    } else {
        UIAlertView *alertError = [[UIAlertView alloc] initWithTitle:@"Login failed"
                                                             message:responseDictionary[@"message"]
                                                            delegate:self
                                                   cancelButtonTitle:@"OK"
                                                   otherButtonTitles:nil];
        [alertError show];
    }
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
    UIAlertView *alertError = [[UIAlertView alloc] initWithTitle:@"Network problem"
                                                        message:[error localizedDescription]
                                                       delegate:self
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
    [alertError show];
}];