Question

我需要按顺序完成以下任务，并在完成所有任务后更新UI。由于数据彼此依赖，我创建了NSOperationQueue *myQueue，但其中一项任务需要很长时间才能完成，而上一项任务不是等待上一个任务完成而只是更新UI

任务顺序应为
1.显示装载中心
2.Parse html get ids
3.用解析的ids下载Json 4.用json填充数据库 4.1这部分还有很多后台工作，填充数据库大约需要5-6秒 5.隐藏装载中心

因此5在4和4.1完成之前执行.... 基本上我想要这个Serial，但这种情况正在发生我想Concurrent 我也试过'dispatch_sync'没有运气

-(void)viewDidAppear:(BOOL)animated
{
    //show hud
    [self performSelectorOnMainThread:@selector(showLoadingHud) withObject:self waitUntilDone:YES];
    [self startProcess];

}

-(void)startProcess
{
    NSOperationQueue *myQueue = [NSOperationQueue mainQueue];
    [myQueue setMaxConcurrentOperationCount:1];

    __block NSMutableArray *imdbIDs=[[NSMutableArray alloc] init];
     NSMutableArray *urlList=[[NSMutableArray alloc] initWithArray:[ImdbURLs getImdburlArray]];

    NSBlockOperation *getiImdbViaHtmlParser = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakHtmlParser = getiImdbViaHtmlParser;

    [weakHtmlParser addExecutionBlock:^{
        //first
        for (NSString *imdbUrl in urlList) {
           ...
    }];

    NSBlockOperation *getJsonFromIMDB = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakGetJsonFromIMDB = getJsonFromIMDB ;

    [weakGetJsonFromIMDB  addExecutionBlock:^{
        //second
        for (NSString *imdbStrings in imdbIDs) {
                //this also calls database methods and populates database with safe threads
                [self AFReqTest:imdbStrings];//I guess this causing the problem
        }
    }];

    NSBlockOperation *checkResult = [[NSBlockOperation alloc] init];
    __weak NSBlockOperation *weakCheckResult = checkResult ;

    [weakCheckResult addExecutionBlock:^{
            //dismiss hud
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                [self dismissLoadingHud];//this is getting called before getJsonFromIMDB block finishes
            }];
    }];

    [checkResult addDependency:getJsonFromIMDB];
    [getJsonFromIMDB  addDependency:getiImdbViaHtmlParser];

    [myQueue addOperation:getJsonFromIMDB];
    [myQueue addOperation:getiImdbViaHtmlParser];
    [myQueue addOperation:checkResult];
}

-(void)AFReqTest:(NSString *)idString
{
    ...//buch of code
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {

       //here I call another background method with result 
      [self insertIntoDatabase:responseObject];

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

}

-(void)insertIntoDatabase:(NSDictionary *)responseObject
{
    ParseImdbResponse *parse=[[ParseImdbResponse alloc] initWithResponseDic:responseObject];
    PopulateDatabase *inserInstance=[[PopulateDatabase alloc] initWithResponseDic:parse];

    dispatch_queue_t insertqueue= dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMoviesTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoGenresTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoActorsTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoDirectorsTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMovieGenresTable];
    });
    dispatch_sync(insertqueue, ^{
        [inserInstance inserIntoMovieCastTable];
    });

}

很抱歉，长代码我不确定问题是我的代码结构还是我错过了什么？

NSOperationQueue块在上一个任务完成之前更新UI

0 个答案: