如何将UIImage保存到文档目录? [英] How to save a UIImage to documents directory?

问题描述

我正在尝试将录制的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，这样我就可以使用该对象来填充集合视图.使用当前(在下面)的代码，在录制视频后，视频路径将保存到documents目录，视频路径和缩略图设置为我的Post对象，并且缩略图会正确显示在我的收藏夹视图中.到目前为止一切都很好.

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.

但是，由于视频路径位于目录中，因此在应用程序重新启动之间只有视频路径存在，而缩略图没有.我也想将缩略图保存在那里，但是我不知道该怎么做，因为看起来您只能将URL写入目录.

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.

这是我第一次使用documents目录，因此将不胜感激！如何将缩略图(UIImage)连同其来源的视频一起写入我的文档目录?

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?

到目前为止，这是我的代码:

Here's my code so far:

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")
        }
    }
}

推荐答案

一个建议:将图像保存到库/缓存"，如果可以按照苹果的指导原则再次下载.

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

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
        }
    }

---

Swift4:

---

Swift4:

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 dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyyMMddhhmmss"

        let filename = dateFormatter.string(from: Date()).appending(".jpg")
        let filepath = directoryPath.appending(filename)
        let url = NSURL.fileURL(withPath: filepath)
        do {
            try chosenImage.jpegData(compressionQuality: 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
        }
    }

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