ios - AFNetworking在下载过程中阻塞主线程

Question

我使用AFNetworking下载了大约200张图片。问题是主线程在下载期间被阻塞，而不是在成功/失败阻塞期间。下面是我的代码：

imageDownloads=[[NSMutableArray alloc]init];
for(NSString *url in liens){
    NSString *totalURL = [NSString stringWithFormat:@"http://%@", url];
    [imageDownloads addObject:[[ImageDownload alloc] initWithURL:[NSURL URLWithString:totalURL] filename:nil]];
}
for (int i=0; i < imageDownloads.count; i++)
{
    ImageDownload *imageDownload = imageDownloads[i];
    [self downloadImageFromURL:imageDownload];
}



   - (void)downloadImageFromURL:(ImageDownload *)imageDownload
{
    NSURLRequest *request = [NSURLRequest requestWithURL:imageDownload.url];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [operation setDownloadProgressBlock:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
        imageDownload.totalBytesRead = totalBytesRead;
        imageDownload.totalBytesExpected = totalBytesExpectedToRead;
        [self updateProgressView];
    }];
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSAssert([responseObject isKindOfClass:[NSData class]], @"expected NSData");

        imageDownload.totalBytesExpected = imageDownload.totalBytesRead;
        [self updateProgressView];
        //all kind of basic stuff here I left out: I get store the data inside CoreData
        NSLog(@"finished %@", imageDownload);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"error %@", error);
    }];
    [operation start];
}

文本。这部分如果真的很快的话。但是我以为AFNetworking不应该在我下载的时候阻塞主线程？这也不允许我跟踪download...Am的进度，我做错了什么或曲解了什么？

Answer 1

您正在更新进度块中的进度视图。因为AFNetworking本质上是异步的，所以这些请求中的每一个都将堆叠并同时运行。如果你正在运行200个这样的应用程序，这会冻结应用程序。尝试使用NSOperationQueue的maxConcurrentOperationCount来限制并发线程的数量。

或者，你也可以省去所有的麻烦，直接使用sdwebimage。