如何将相机胶卷中的视频添加到 Xcode（Swift）上的应用程序 [关闭]

Question

我希望用户能够从他们的相机胶卷中导入视频，对其进行编辑，然后将视频保存到他们的相机胶卷中。我该怎么做？

Answer 1

嗯，首先你需要像这样询问用户的权限：

AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { response in
    if response {
        //access granted
    } else {

    }
}

//Photos
let photos = PHPhotoLibrary.authorizationStatus()
if photos == .notDetermined {
    PHPhotoLibrary.requestAuthorization({status in
        if status == .authorized{
            ...
        } else {}
    })
}

然后你需要在 plist 文件中添加一些关于你为什么想要它的描述，如下所示：

<key>NSCameraUsageDescription</key>
<string>You can take photos</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>You can select photos to attach it on this app.</string>

关于剪辑视频，这是一个非常主观的话题。你需要做什么样的改变？而且取决于你想要做什么，它可能会非常复杂。

稍后保存到相机胶卷，我得到了一个下载文件并将其保存到相机胶卷的代码示例：

import AssetsLibrary

...
...

func downloadVideoToCameraRoll() {

// Local variable pointing to the local file path for the downloaded video
var localFileUrl: String?

// A closure for generating the local file path for the downloaded video. This will be pointing to the Documents directory with a unique UDID file name.
let destination: (NSURL, NSHTTPURLResponse) -> (NSURL) = {
    (temporaryURL, response) in

    if let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as? NSURL {
        let finalPath = directoryURL.URLByAppendingPathComponent("\(NSUUID()).\(response.suggestedFilename!)")
        localFileUrl = finalPath.absoluteString
        return finalPath
    }

    return temporaryURL
}

// The media post which should be downloaded
let postURL = NSURL(string: "https://api.instagram.com/v1/media/" + "952201134785549382_250131908" + "?access_token=" + InstagramEngine.sharedEngine().accessToken)!

// Then some magic happens that turns the postURL into the videoURL, which is the actual url of the video media:
let videoURL = NSURL(string: "https://scontent.cdninstagram.com/hphotos-xfp1/t50.2886-16/11104555_1603400416544760_416259564_s.mp4")!

// Download starts
let request = Alamofire.download(.GET, videoURL, destination)

// Completion handler for the download
request.response { (request, response, data, error) -> Void in
    if let path = localFileUrl {
        let isVideoCompatible = UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(path)
        println("bool: \(isVideoCompatible)") // This logs out "bool: false"

        let library = ALAssetsLibrary()

        library.writeVideoAtPathToSavedPhotosAlbum(NSURL(string: path), completionBlock: { (url, error) -> Void in
            // Done! Go check your camera roll
        })
    }
}
}

祝你好运！