ios - 检查多个异步网络操作何时完成

Question

我的应用程序从 Flickr 上的用户那里下载大量信息和图像，并且我使用 AFHttpClient。所以基本上，每个人都会异步地执行有效的 NSUrlConnection 操作，然后运行完成 block 。一个类为每个 api 调用提供方法，另一个类循环执行 api 调用以获取每个用户数据，并将其放入核心数据中。但是，我的问题是，我无法找到一种方法让调用 api 类的类确定所有下载何时完成并将其放入核心数据中。另外，我将同时下载多个用户数据，并且不同的属性根据用户以不同的顺序完成加载。有什么建议吗？

Answer 1

AFNetworking 使管理多个请求和最终回调变得非常简单，只需使用:

- (void)enqueueBatchOfHTTPRequestOperations:(NSArray *)operations 
                          progressBlock:(void (^)(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations))progressBlock 
                        completionBlock:(void (^)(NSArray *operations))completionBlock;

或

- (void)enqueueBatchOfHTTPRequestOperationsWithRequests:(NSArray *)urlRequests
                                      progressBlock:(void (^)(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations))progressBlock 
                                    completionBlock:(void (^)(NSArray *operations))completionBlock;

在 AFHHTPClient 实例上。

示例:

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@""]];
NSURLRequest *otherRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:@""]];

AFHTTPRequestOperation *operationForImages = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operationForImages setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

    //success of images request
    self.imageDictionary = responseObject;

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

    //manage error for this request

}];
AFHTTPRequestOperation *operationForText = [[AFHTTPRequestOperation alloc] initWithRequest:otherRequest];
[operationForText setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

    //success of text request
    self.textDictionary = responseObject;

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

    //manage error for this request

}];


[[MyPersonalAFHTTPClient sharedClient] enqueueBatchOfHTTPRequestOperations:@[operationForImages,operationForText] progressBlock:^(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations) {

    //track progression of requests

} completionBlock:^(NSArray *operations) {

    //all the request are completed

}];