Swift - 从远程 URL 下载视频并将其保存在相册中 [英] Swift - Download a video from distant URL and save it in an photo album

问题描述

我目前正在我的应用中显示一个视频，我希望用户能够将其保存到其设备画廊/相册照片/相机胶卷中.这是我正在做的，但视频未保存在相册中:/

I'm currently displaying a video in my app and I want the user to be able to save it to its device gallery/album photo/camera roll. Here it's what I'm doing but the video is not saved in the album :/

    func downloadVideo(videoImageUrl:String)
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
        //All stuff here

        print("downloadVideo");
        let url=NSURL(string: videoImageUrl);
        let urlData=NSData(contentsOfURL: url!);

        if((urlData) != nil)
        {
            let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0];

            let fileName = videoImageUrl; //.stringByDeletingPathExtension

            let filePath="(documentsPath)/(fileName)";

            //saving is done on main thread

            dispatch_async(dispatch_get_main_queue(), { () -> Void in

                urlData?.writeToFile(filePath, atomically: true);
                print("videoSaved");
            })

        }
    })

}

我也在研究这个:

let url:NSURL = NSURL(string: fileURL)!;

    PHPhotoLibrary.sharedPhotoLibrary().performChanges({
        let assetChangeRequest = PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(url);
        let assetPlaceHolder = assetChangeRequest!.placeholderForCreatedAsset;
        let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: self.assetCollection)
        albumChangeRequest!.addAssets([assetPlaceHolder!])
        }, completionHandler: saveVideoCallBack)

但我有错误无法从文件(空)创建数据".我的资产变更请求"为零.我不明白，因为我的 url 是有效的，当我使用浏览器访问它时，它会下载一个快速时间文件.

But I have the error "Unable to create data from file (null)". My "assetChangeRequest" is nil. I don't understand as my url is valid and when I go to it with a browser, it download a quick time file.

如果有人可以帮助我，将不胜感激！我正在使用 Swift 并以 iOS 8.0 为目标.

If anyone can help me, it would be appreciated ! I'm using Swift and targeting iOS 8.0 min.

推荐答案

更新

想使用 URLSession 更新 Swift 3 的答案，并发现相关主题中已经存在答案这里.使用它.

Wanted to update the answer for Swift 3 using URLSession and figured out that the answer already exists in related topic here. Use it.

原答案

下面的代码将视频文件保存到相机胶卷.我重用了你的代码，做了一个小改动 - 我删除了 let fileName = videoImageUrl; 因为它会导致不正确的文件路径.

The code below saves a video file to Camera Roll. I reused your code with a minor change - I removed let fileName = videoImageUrl; because it leads to incorrect file path.

我测试了此代码并将资产保存到相机胶卷中.您询问要在 creationRequestForAssetFromVideoAtFileURL 中放入什么内容 - 如下例所示放入下载的视频文件的链接.

I tested this code and it saved the asset into camera roll. You asked what to place into creationRequestForAssetFromVideoAtFileURL - put a link to downloaded video file as in the example below.

let videoImageUrl = "http://www.sample-videos.com/video/mp4/720/big_buck_bunny_720p_1mb.mp4"

DispatchQueue.global(qos: .background).async {
    if let url = URL(string: urlString),
        let urlData = NSData(contentsOf: url) {
        let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0];
        let filePath="(documentsPath)/tempFile.mp4"
        DispatchQueue.main.async {
            urlData.write(toFile: filePath, atomically: true)
            PHPhotoLibrary.shared().performChanges({
                PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: URL(fileURLWithPath: filePath))
            }) { completed, error in
                if completed {
                    print("Video is saved!")
                }
            }
        }
    }
}

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