ios - AFNetworking 响应显示在日志中，但在调试器中为零

Question

我正在使用 AFNetworking 获取 JSON 响应。我得到的是 PhotoPXArray(我使用 mantle 创建的模型)。日志输出正是我想要的数据。我的问题是使用数据。当我设置一个断点并查看 responseObject 时，它是零。我不知道为什么日志正在抽出数据，但调试器中的值为 nil。

我最终想做的是保存响应以备后用。

此外，我正在使用 Sculptor 来帮助进行序列化。

-(NSArray*) getPhotoForWord:(NSString*)word {
    NSArray *results = nil;
    __block NSMutableDictionary *test = nil;

    NSString *requestString = BASE_URL;
    requestString = [requestString stringByAppendingString:@"photos/search?term="];
    requestString = [requestString stringByAppendingString:word];
    requestString = [requestString stringByAppendingString:CONSUMER_KEY];



    NSString *encoded = [requestString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    manager.responseSerializer = [SCLMantleResponseSerializer serializerForModelClass:PhotoPXArray.class];
    [manager GET:encoded
      parameters:nil
         //success:^(AFHTTPRequestOperation *operation, id responseObject) {
         success:^(AFHTTPRequestOperation *operation, id responseObject) {
             NSLog(@"JSON: %@", responseObject);
             test = responseObject;

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


    return results;
}

Answer 1

您永远不会设置results 变量，所以当然会返回nil。即使您使用了 test(您确实设置了)，那也是异步发生的，所以当您立即返回时，它也将是 nil，只会得到 responseObject 稍后的值。

您可能会考虑采用异步模式，而不是提供完成处理程序参数:

- (void)getPhotoForWord:(NSString*)word completionHandler:(void (^)(id responseObject, NSError *error))completionHandler{
    NSString *requestString = BASE_URL;
    requestString = [requestString stringByAppendingString:@"photos/search?term="];
    requestString = [requestString stringByAppendingString:word];
    requestString = [requestString stringByAppendingString:CONSUMER_KEY];

    NSString *encoded = [requestString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    manager.responseSerializer = [SCLMantleResponseSerializer serializerForModelClass:PhotoPXArray.class];
    [manager GET:encoded parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        if (completionHandler) {
            completionHandler(responseObject, nil);
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        if (completionHandler) {
            completionHandler(nil, error);
        }
    }];
}

然后你可以这样调用它:

[obj getPhotoForWord:word completionHandler:^(id responseObject, NSError *error) {
    // use responseObject here
}];

// do not use it here because the above happens asynchronously (i.e. later)