Ios 暂停并恢复网络队列

我正在使用ASINetworkQueue在iPad应用程序中下载大约50个文件。我正在寻找一种允许用户暂停并恢复队列的方法

ASIHTTP文档参考

[request setAllowResumeForFileDownloads:YES];

但这是在单个请求级别操作的，而不是在队列级别。因为ASINetworkQueue是NSOperationQueue的一个子类，所以我也尝试过

[queue setSuspended:YES];

虽然这会暂停队列，但它不会影响正在进行的下载，它只是等待下载完成，然后暂停队列，在我的情况下，这意味着用户按下按钮和队列实际暂停之间有很多秒，这不是我想要的UI体验

有人能提出另一种解决这个问题的方法吗？

我的解决方案

- (void) pause
{
    if(self.queue && self.queue.requestsCount>0)
    {
        NSLog(@"%@", self.queue.operations);

        for (ASIHTTPRequest * req in self.queue.operations) {
            req.userInfo = [NSDictionary dictionaryWithObject:@"1" forKey:@"ignore"];
        }

        [self.queue.operations makeObjectsPerformSelector:@selector(cancel)];

        [self.queue setSuspended:YES];

        for (ASIHTTPRequest * req in self.queue.operations) {
            ASIHTTPRequest * newReq = [[ASIHTTPRequest alloc] initWithURL:req.url];
            [newReq setDownloadDestinationPath:req.downloadDestinationPath];
            [newReq setTemporaryFileDownloadPath:req.temporaryFileDownloadPath];
//            [newReq setAllowResumeForFileDownloads:YES];
            [newReq setUserInfo:req.userInfo];
            [self.queue addOperation:newReq];

        }

    }
}

- (void) resume
{
    if(self.queue && self.queue.requestsCount>0)
    {
        [self _setupQueue];
        [self.queue go];
    }
}

- (void) _setupQueue
{
    [self.queue setShouldCancelAllRequestsOnFailure:NO];
    [self.queue setRequestDidStartSelector:@selector(downloadDidStart:)];
    [self.queue setRequestDidFinishSelector:@selector(downloadDidComplete:)];
    [self.queue setRequestDidFailSelector:@selector(downloadDidFailed:)];
    [self.queue setQueueDidFinishSelector:@selector(queueDidFinished:)];
    [self.queue setDownloadProgressDelegate:self.downloadProgress];
    [self.queue setDelegate:self];
    self.queue.maxConcurrentOperationCount = 3;
//    self.queue.showAccurateProgress = YES;
}

首先，暂停功能取消所有正在运行的操作，并重新创建新请求，将它们推入队列。 然后resume函数取消队列的挂起。 请注意，请求不应设置setAllowResumeForFileDownloads:YES，否则totalBytesToDownload将计算错误。如果allowResumeForFileDownloads=NO，其值将与队列中的请求计数相同

这是我的请求失败处理程序，我在文件下载失败时添加了重试。但是当我取消一个请求时，我不做什么，重试机制将被调用，所以我将userInfoignore:true设置为request对象以防止它发生

- (void) downloadDidFailed:(ASIHTTPRequest *)req
{
    NSLog(@"request failed");
    NSLog(@"%d", self.queue.requestsCount);

    if(![self.queue showAccurateProgress])
    {
        [self.queue setTotalBytesToDownload:[self.queue totalBytesToDownload]-1];
        NSLog(@"totalBytesToDownload=%lld", self.queue.totalBytesToDownload);
    }

    NSDictionary * userInfo = req.userInfo;
    if([[userInfo valueForKey:@"ignore"] boolValue]) return; // ignore retry

    int retryTimes = [[req.userInfo objectForKey:@"retryTimes"] intValue];
    if(retryTimes<kMU_MaxRetry)
    {
        ++ retryTimes;
        NSLog(@"retry %d", retryTimes);
        ASIHTTPRequest * newReq = [ASIHTTPRequest requestWithURL:req.url];
        [newReq setDownloadDestinationPath:req.downloadDestinationPath];
        [newReq setTemporaryFileDownloadPath:req.temporaryFileDownloadPath];
        newReq.userInfo = [NSDictionary dictionaryWithObject:[NSString stringWithFormat:@"%d", retryTimes] forKey:@"retryTimes"];
        [self.queue addOperation:newReq];

        NSLog(@"%d", self.queue.requestsCount);
    }else{  // reach max retry, fail it
        [self.failures addObject:req];
    }
}

我不确定是否有更好的解决方案，希望它能帮助您