如何将相机胶卷中的视频添加到Xcode上的应用程序（Swift）

Question

我希望用户能够从相机胶卷导入视频，进行编辑，然后将视频保存到相机胶卷中。我怎样才能做到这一点？

Answer 1

嗯，首先你要问用户的权限是这样的：

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，你需要把你为什么想在plist文件的一些描述如图所示波纹管：

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

关于编辑视频，这是一个非常主观的主题。你需要做什么样的改变？取决于你想做什么，它可能非常复杂。

后来保存到相机胶卷，我得到了下载文件并将其保存到相机胶卷中的代码示例：

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！