ios - AF 网络 2.0 : AFHTTPRequestOperationManager asynchronous methode invoke

Question

我正在使用 AFNetworking 2.0 为我的应用程序联网，我已经实现了一种检查用户登录的方法

-(NSString *) loginWith : (NSString *) email andPassword :(NSString *) password
{
    __block NSString * result ;

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

    NSDictionary *params = @{@"email": email, @"password": password};

    manager.responseSerializer = [AFJSONResponseSerializer serializer];

    [manager POST:[kROOT_URL stringByAppendingString:@"auth/"] parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject)
    {
        NSLog(@"JSON: %@", (NSDictionary*)responseObject);

        [[NSUserDefaults standardUserDefaults] setObject:responseObject forKey:USER_KEY];
        [[NSUserDefaults standardUserDefaults] synchronize];

        result = [responseObject objectForKey:@"id"];
        NSLog(@"result :: %@",result);

    } failure:^(AFHTTPRequestOperation *operation, NSError *error)
    {
        NSLog(@"Error: %@", error);

        result = nil;

    }];

    return result;
}

我正在从其他 View Controller 调用此方法:

NSString * result = [self.user loginWith:emailCell.textField.text andPassword:passCell.textField.text];

NSLog(@"Result: %@",result);

问题是我得到“null”作为结果的对象，这是因为当执行 NSlog 时，网络进程在后台线程中进行，所以我如何更正实现，这样我才能得到结果在适当的时候，在获取之后

谢谢

Answer 1

您应该在方法签名中添加一个“回调” block 参数，并在请求完成时调用该 block 。

- (void)loginWith:(NSString *)email andPassword:(NSString *)password complete:(void(^)(id result, NSError *error))block {

    // ...

    [manager POST:[kROOT_URL stringByAppendingString:@"auth/"] parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject)
    {

        // ...

        result = [responseObject objectForKey:@"id"];

        if (block) block(result, nil)

    } failure:^(AFHTTPRequestOperation *operation, NSError *error)
    {

        if (block) block(nil, error)

    }];

}

调用该方法时，传递回调 block ，您可以在其中读取结果值:

[self.user loginWith:emailCell.textField.text andPassword:passCell.textField.text complete:^(id result, NSError *error) {
     if (error)
         NSLog(@"Error: %@", error);
     else
         NSLog(@"Result: %@", result);
}];