在缓存中保存视频

Question

有没有办法将视频保存在缓存中,然后在需要时将其恢复？

NSCache *memoryCache; //assume there is a memoryCache for images or videos
NSString *urlString = @"http://blog.jimdo.com/wp-content/uploads/2014/01/tree-247122.jpg";
NSString *path = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"A"] ofType:@"mov"];
NSURL *url = [NSURL fileURLWithPath:path];

NSData *downloadedData = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlString]];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^
{
    if (downloadedData)
    {
        // STORE IN FILESYSTEM
        NSString* path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
        NSString *file = [path stringByAppendingPathComponent:@"B.mov"];
        [downloadedData writeToFile:file options:NSDataWritingAtomic error:nil];
        NSLog(@"Cache File : %@", file);

        // STORE IN MEMORY
        [memoryCache setObject:downloadedData forKey:@"B.mov"];
    }
    // NOW YOU CAN CREATE AN AVASSET OR UIIMAGE FROM THE FILE OR DATA

});

我在Stack Overflow上找到了这个代码,但它似乎不起作用.

Answer 1

您可以用于NSURLSessionDownloadTask下载视频或图像，直接写入临时目录。

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下载期间，会话定期调用 delegate\xe2\x80\x99s\n URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:\n 方法并提供状态信息。

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完成后，会话调用 delegate\xe2\x80\x99s URLSession:downloadTask:didFinishDownloadingToURL:\n 方法或完成处理程序。在该方法中，您必须打开文件进行读取，或者将其移动到 app\xe2\x80\x99s 沙箱容器目录中的永久位置。

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NSURL *URL = [NSURL URLWithString:@"http://blog.jimdo.com/wp-content/uploads/2014/01/tree-247122.jpg"];\nNSURLRequest *request = [NSURLRequest requestWithURL:URL];\n\nNSURLSession *session = [NSURLSession sharedSession];\nNSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request\n                                                     completionHandler:\n^(NSURL *location, NSURLResponse *response, NSError *error) {\n    NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];\n    NSURL *documentsDirectoryURL = [NSURL fileURLWithPath:documentsPath];\n    NSURL *documentURL = [documentsDirectoryURL URLByAppendingPathComponent:[response \n    suggestedFilename]];\n    [[NSFileManager defaultManager] moveItemAtURL:location\n                                            toURL:documentURL\n                                            error:nil];\n  }];\n\n  [downloadTask resume];\n

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NSURLSessionDownloadTask 类参考

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