正确初始化PHAssetCollection的探讨

Question

对于如何正确初始化相机应用程序中的PHAssetCollection，以便将视频保存到相册中，我有些困惑。我并没有试图对相册中的任何视频或图片做任何事情，我只是试图通过我的相机应用程序将捕获的视频保存到相册中，这个应用程序是围绕AVFoundation开发的。苹果在这方面的文档很少，我在这里看到的所有问题都没有完全解决这个问题。我是否应该在这个任务中使用一个资产集合？还是有一个更简单的方式使用Photos框架？

下面是在视频开始并完成录制时调用的委托函数

        println("capture output : finish recording to \(outputFileURL)")

        self.weAreRecording = false
        self.isSessionRunning = false

        println("Getting moments in photo library")

        let results: PHFetchResult = PHAssetCollection.fetchAssetCollectionsWithType(PHAssetCollectionType.Moment, subtype: PHAssetCollectionSubtype.AlbumRegular, options: nil)

        var assetCollection: PHAssetCollection?

//        SHOULD I EVEN BE DOING THIS??? IM NOT TRYING TO DO ANYTHING IN THE PHOTOS ALBUM

//        results.enumerateObjectsUsingBlock { (object, index, stop) -> Void in
//            
//            let assetCollection: PHAssetCollection = object as! PHAssetCollection
//            
//            momentsCount++
//            
//            blah blah blah
//            
//        }

        let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT

        dispatch_async(dispatch_get_global_queue(priority, 0), {

            PHPhotoLibrary.sharedPhotoLibrary().performChanges({

                let request = PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(outputFileURL)

                let assetPlaceholder = request.placeholderForCreatedAsset

                // The problem is here, since I am not entirely sure how to go about initializing
                // The assetCollection correctly
                let albumChangeRequest = PHAssetCollectionChangeRequest(forAssetCollection: assetCollection, assets: results)

                albumChangeRequest.addAssets([assetPlaceholder])

                }, completionHandler: {(success, error) in

                    if success {

                         NSLog("Adding video to Library -> %@", (success ? "Sucess" : "Error!"))
                    }
                    else {

                        println("There was an error saving the video")
                    }
            })

        })
    }

    func captureOutput(captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAtURL fileURL: NSURL!, fromConnections connections: [AnyObject]!) {

        println("capture output: started recording to \(fileURL)")

        self.isSessionRunning = true
        self.weAreRecording = true
    }

Answer 1

我认为你对PHAssetCollection的所有谈论都是一只青鱼。因为您只想将视频保存到摄像机名册中，请拨打UISaveVideoAtPathToSavedPhotosAlbum。

如果出于某些原因，您不愿意这样做，那么只需直接保存到照片库，大致如下(直接输入，没有测试，可能需要一些轻微的mods)：

PHPhotoLibrary.sharedPhotoLibrary().performChanges({
    PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(f)
    }, completionHandler: {
        (ok:Bool, err:NSError!) in
        // whatever
})