Question

我正在使用RestKit（0.20）/ JSON从Web服务获取数据。到目前为止，我已经为少量数据工作了，但我需要这项工作用于10,000多条记录。因为获取数据可能需要相当长的时间（特别是通过3G或更慢的连接）我想把它切成碎片但是我遇到线程问题。我想：

获取1000条记录
将它们映射到对象
将它们推入SQLlite数据库
更新进度条UI
如果还有更多要获取的内容再次转到1

到目前为止我的代码是：

- (void) loadPeople {
.. not so relevant code and setup ..

 peoplePath = [NSString stringWithFormat:@"http://mywebservice.com/api/v2/people?columns=id,first_name,last_name&sort=updated_at&limit=1000&offeset=%d",offset];
 NSURLRequest *request = [objectManager requestWithObject:nil method:RKRequestMethodGET path: peoplePath parameters:nil];

    RKObjectRequestOperation *operation = [[RKObjectRequestOperation alloc] initWithRequest:request responseDescriptors:@[responseDescriptor]];

    [operation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
        [Person savePeople:mappingResult.array];
        [self updatePeopleProgressBar];

    } failure:^(RKObjectRequestOperation *operation, NSError *error)
     {
         NSLog (@"Error: %@", error);
         NSLog (@"Response:  %@", operation.HTTPRequestOperation.responseString);
     }];
    [operation start];
}

应该一次又一次地执行从peoplePath开始的部分（将偏移量变量增加1000），但我对实现循环的位置一无所知。但是，它应该只在当前保存和更新完成后执行下一次迭代：我正在跟踪已保存的数量，以防用户退出应用程序，以便下次我可以恢复。所以我需要某种顺序线程......

我想问题在于我对块和多线程的熟悉知识。谁能给我一个如何做到这一点的线索。

更新方法：

- (void) loadPeople : (NSInteger) offset {
    NSString *apiKey = self.APIKey;

    NSIndexSet *statusCodeSet = RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful);
    RKMapping *mapping = [Mappings peopleMapping];
    NSString *pathPattern = [NSString stringWithFormat:@"%@/people",basePathPattern];
    RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:mapping
                                                                                            method:RKRequestMethodAny
                                                                                       pathPattern:pathPattern
                                                                                           keyPath:keyPath
                                                                                       statusCodes:statusCodeSet];
    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://%@/%@",[self clientURLPart],basePathPattern]];

    RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL:url];
    [[[RKObjectManager sharedManager] HTTPClient] setDefaultHeader:@"X-API-KEY" value:apiKey];

    [[[RKObjectManager sharedManager] HTTPClient] setDefaultHeader:@"Content-type application" value:@"json" ];
    [[[RKObjectManager sharedManager] HTTPClient] setDefaultHeader:@"Accept application" value:@"json"];


    NSString *peoplePath = [NSString stringWithFormat:@"%@/%@?columns=id,first_name,last_name&sort=updated_at&limit=4&offset=%d",[self clientURLPart],basePathPattern,offset];

    NSURLRequest *request = [objectManager requestWithObject:nil method:RKRequestMethodGET path:peoplePath parameters:nil];


    RKObjectRequestOperation *operation = [[RKObjectRequestOperation alloc] initWithRequest:request responseDescriptors:@[responseDescriptor]];

    [operation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
        [Person savePeople:mappingResult.array];
        NSLog(@"Foundrecords %d",[mappingResult.array count]);
        if ([mappingResult.array count] == 4) {
            [self loadPeople:(offset + 4)];
        }

    } failure:^(RKObjectRequestOperation *operation, NSError *error)
     {
         NSLog (@"Error: %@", error);
         NSLog (@"Response:  %@", operation.HTTPRequestOperation.responseString);
     }];
    [operation start];
}

Answer 1

您显示的代码应该是一个采用页码或偏移号的方法。然后，在成功块中，您可以调用方法（递归类型）以使用来自“当前”下载的适当信息开始下一次下载。这可以避免所有与线程相关的问题。

Restkit按顺序进行线程化

1 个答案: