如何将UIImage保存到文档目录？

I'm trying to save both a recorded video's file path, and a thumbnail from the video to the documents directory. Then, set those two values to an object using the file paths so I can use the object to populate a collection view. With the code I have currently (below), after I record a video, the video path gets saved to the documents directory, and the video path and thumbnail get set to my Post object, and the thumbnail appears properly in my collection view. All good so far.

我正在尝试将录制视频的文件路径和缩略图从视频保存到文档目录。然后,使用文件路径将这两个值设置为对象,以便我可以使用该对象填充集合视图。使用我目前(下面)的代码,在录制视频后,视频路径被保存到文档目录,视频路径和缩略图被设置为我的Post对象,缩略图在我的集合视图中正确显示。到目前为止都很好。

However only the video path persists between app re-launches since it's in the directory, and the thumbnail isn't. I'd like to save the thumbnail there too but I don't know how to go about it since it appears you can only write URLs to the directory.

但是,只有视频路径在应用程序重新启动之间持续存在,因为它位于目录中,而缩略图则不然。我也想在那里保存缩略图,但我不知道如何去做,因为看起来你只能写URL到目录。

This is my first experience with utilizing the documents directory so any help will be appreciated! How can I write the thumbnail (UIImage) to my documents directory along with the video it's from?

这是我第一次使用文档目录,所以任何帮助将不胜感激!如何将缩略图(UIImage)与其来自的视频一起写入我的文档目录?

Here's my code so far:

到目前为止,这是我的代码:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

    let mediaType = info[UIImagePickerControllerMediaType] as! NSString
    dismiss(animated: true, completion: nil)

    if mediaType == kUTTypeMovie {
        // Componenets for a unique ID for the video
        var uniqueVideoID = ""
        var videoURL:NSURL? = NSURL()
        var uniqueID = ""
        uniqueID = NSUUID().uuidString

        // Get the path as URL
        videoURL = info[UIImagePickerControllerMediaURL] as? URL as NSURL?
        let myVideoVarData = try! Data(contentsOf: videoURL! as URL)

        // Write the video to the Document Directory at myVideoVarData (and set the video's unique ID)
        let docPaths = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)
        let documentsDirectory: AnyObject = docPaths[0] as AnyObject
        uniqueVideoID = uniqueID  + "VIDEO.MOV"
        let docDataPath = documentsDirectory.appendingPathComponent(uniqueVideoID) as String
        try? myVideoVarData.write(to: URL(fileURLWithPath: docDataPath), options: [])
        print("docDataPath under picker ", docDataPath)
        print("Video saved to documents directory")

        // Create a thumbnail image from the video (first frame)
        let asset = AVAsset(url: URL(fileURLWithPath: docDataPath))
        let assetImageGenerate = AVAssetImageGenerator(asset: asset)
        assetImageGenerate.appliesPreferredTrackTransform = true
        let time = CMTimeMake(asset.duration.value / 3, asset.duration.timescale)
        if let videoImage = try? assetImageGenerate.copyCGImage(at: time, actualTime: nil) {
            // Add thumbnail & video path to Post object
            let video = Post(pathToVideo: URL(fileURLWithPath: docDataPath), thumbnail: UIImage(cgImage: videoImage))
            posts.append(video)
            print("Video saved to Post object")
        }
    }
}

1 个解决方案

#1

As simple as this:

就这么简单:

func saveImageToDocumentDirectory(_ chosenImage: UIImage) -> String {
        let directoryPath =  NSHomeDirectory().appending("/Documents/")
        if !FileManager.default.fileExists(atPath: directoryPath) {
            do {
                try FileManager.default.createDirectory(at: NSURL.fileURL(withPath: directoryPath), withIntermediateDirectories: true, attributes: nil)
            } catch {
                print(error)
            }
        }
        let filename = NSDate().string(withDateFormatter: yyyytoss).appending(".jpg")
        let filepath = directoryPath.appending(filename)
        let url = NSURL.fileURL(withPath: filepath)
        do {
            try UIImageJPEGRepresentation(chosenImage, 1.0)?.write(to: url, options: .atomic)
            return String.init("/Documents/\(filename)")

        } catch {
            print(error)
            print("file cant not be save at path \(filepath), with error : \(error)");
            return filepath
        }
    }

One Suggestion: Save images to Library/Caches if that can be downloaded again as per apple's guide line.

一个建议:如果可以按照苹果的指南再次下载图像,则将图像保存到库/缓存中。

#1