Question

以下是照片应用的代码。

  class VideoList_TableViewController: UITableViewController {
    var videoAssets:PHFetchResult<PHAsset>?
    var imageManager:PHImageManager?
    override func viewDidLoad() {
        super.viewDidLoad()
        self.imageManager = PHImageManager()

    }


    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int 
    {

      // here i am fetching assets 
       videoAssets = PHAsset.fetchAssets(with: .video, options:nil)
        return 1
    }

    override func tableView(_ tableView: UITableView, 
    numberOfRowsInSection section: Int) -> Int {
     print((videoAssets?.count)!)
        return  (videoAssets?.count)!
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "videoList_Table_Cell", for: indexPath) as! videoList_TableView_Cell_Controller
        if (!cell.didLoaded) {
        cell.didLoaded = true
        cell.asset = videoAssets?[indexPath.row]
        cell.imageManager = self.imageManager
        }
        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
       let cell = tableView.cellForRow(at: indexPath) as! videoList_TableView_Cell_Controller

                    let playerController = AVPlayerViewController()
                    let player = AVPlayer(url: cell.videoUrl!)
                    playerController.player = player
                    self.present(playerController, animated: true, completion: nil)
                    playerController.player?.play()
          }
}

videoList_TableView_Cell_Controller

class videoList_TableView_Cell_Controller: UITableViewCell {
    var imageManager:PHImageManager?
    var videoUrl:URL?
    var didLoaded =  false
    var asset:PHAsset? {
        didSet {
            DispatchQueue.global().async {
                self.imageManager?.requestAVAsset(forVideo: self.asset!, options: nil, resultHandler: { (vAsset, audio, info) in
                    let avUrl = vAsset as? AVURLAsset
                    let vurl = avUrl?.url
                    let imageGenerator = AVAssetImageGenerator(asset:vAsset!)
                    let time = CMTimeMakeWithSeconds(1.0, 1)
                    var actualTime : CMTime = CMTimeMake(0, 0)
                    let myImage = try! imageGenerator.copyCGImage(at: time, actualTime: &actualTime)
                    DispatchQueue.main.async {
                        self.videoUrl = vurl
                        self.videoTypeLbl.text = vurl?.pathExtension
                        self.videoNameLbl.text = vurl?.lastPathComponent
                        self.videoDurationLbl.text = String(CMTimeGetSeconds((vAsset?.duration)!))
                        self.imageV.image = UIImage(cgImage:myImage)
                    }
                })
            }
        }
    }
    @IBOutlet weak var imageV: UIImageView!
    @IBOutlet weak var videoTypeLbl: UILabel!
    @IBOutlet weak var videoDurationLbl: UILabel!
    @IBOutlet weak var videoNameLbl: UILabel!
}

这是swift3 + xcode 8.2中视频播放应用的代码。问题是，当我运行此代码时，我的应用程序占用了太多内存。我认为这是因为我正在获取所有视频资产。有没有什么好方法可以获取资产？

Answer 1

您可以在TableView的cellForItemAt方法中获取有关PHAsset的详细信息。这可能会解决您的问题

    var videos: PHFetchResult<PHAsset>!
    override func viewDidLoad() {
        super.viewDidLoad()
        getVideos()
    }

在获取视频功能中，您可以重新加载TableView。

func getVideos() {
        let options = PHFetchOptions()
        options.sortDescriptors = [ NSSortDescriptor(key: "creationDate", ascending: false) ]
        options.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.video.rawValue)
        videos = PHAsset.fetchAssets(with: options)
        tableView.reloadData() // reload your TableView
    }

在这里，我们调用tableView方法和委托返回PHAsset的数量

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return  videos.count
    }

获取有关PHAsset的信息

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let cell = tableView.dequeueReusableCell(withIdentifier: "videoList_Table_Cell", for: indexPath) as! videoList_TableView_Cell_Controller
            let asset = videos!.object(at: indexPath.row)
             PHImageManager.default().requestAVAsset(forVideo: asset, options: nil, resultHandler: { (vAsset, audio, info) in
                let avUrl = vAsset as? AVURLAsset
                let vurl = avUrl?.url
                let imageGenerator = AVAssetImageGenerator(asset:vAsset!)
                let time = CMTimeMakeWithSeconds(1.0, 1)
                var actualTime : CMTime = CMTimeMake(0, 0)
                let myImage = try! imageGenerator.copyCGImage(at: time, actualTime: &actualTime)

                    cell.videoUrl = vurl
                    cell.videoTypeLbl.text = vurl?.pathExtension
                    cell.videoNameLbl.text = vurl?.lastPathComponent
                    cell.videoDurationLbl.text = String(CMTimeGetSeconds((vAsset?.duration)!))
                    cell.imageV.image = UIImage(cgImage:myImage)

            })
            return cell
        }

处理单元格点击

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
       let cell = tableView.cellForRow(at: indexPath) as! videoList_TableView_Cell_Controller

                    let playerController = AVPlayerViewController()
                    let player = AVPlayer(url: cell.videoUrl!)
                    playerController.player = player
                    self.present(playerController, animated: true, completion: nil)
                    playerController.player?.play()
          }
}

我想快速制作视频应用程序轻量级

1 个答案: