ios - 使用 Swift 和 AVPlayer，如何通过代码添加和删除视频？

Question

我是 Swift 的新手，正在尝试将视频添加到视图中，然后在发送我的“stopScreenSaver”通知时将其删除。除了我去删除视频层（playerLayer.removeFromSuperlayer（））之外，一切似乎都运行良好。

任何指导将不胜感激。我觉得我在这里缺少一些用于添加和删除图层的基本概念！

    import UIKit
    import AVFoundation
    import QuartzCore
    import CoreMedia

    class ViewController: UIViewController {

        let contentURL = NSBundle.mainBundle().URLForResource("testvideo", withExtension: "mp4")
        var player = AVPlayer()
        var playerLayer = AVPlayerLayer()
        let screenSize : CGRect = UIScreen.mainScreen().bounds

        override func viewDidLoad() {
            super.viewDidLoad()
            // Used for starting and stopping the videos related to the screen saver
            NSNotificationCenter.defaultCenter().addObserver(self, selector: "playScreenSaver:", name: "playScreenSaverID", object: nil)
            NSNotificationCenter.defaultCenter().addObserver(self, selector: "stopScreenSaver:", name: "stopScreenSaverID", object: nil)
}

        override func viewDidAppear(animated: Bool) {
            // Player
            player = AVPlayer(URL: contentURL!)

            // Layer for display… Video plays at the full size of the iPad
            playerLayer = AVPlayerLayer(player: player)
            var view = UIView(frame: CGRectMake(0, 0, screenSize.width, screenSize.height))
            self.view.layer.addSublayer(playerLayer)
            playerLayer.frame = view.bounds
        }

        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
        }


    func playScreenSaver(notification: NSNotification){
            print("play")
            dispatch_async(dispatch_get_main_queue()) {
               self.view.layer.addSublayer(self.playerLayer!)
               self.player!.play()
            }
    }

    func stopScreenSaver(notification: NSNotification){
            print("pause")
            dispatch_async(dispatch_get_main_queue()) {
               self.player!.pause()
               self.playerLayer!.removeFromSuperlayer()
            }
    }

}

Answer 1

使用调度解决了我遇到的问题。

dispatch_async(dispatch_get_main_queue()) {
    self.player!.pause()
    self.playerLayer!.removeFromSuperlayer()
 }

Answer 2

override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        DispatchQueue.main.async {
            self.player.currentItem?.removeObserver(self, forKeyPath: "duration", context: nil)
            self.player!.pause()
            self.playerLayer!.removeFromSuperlayer()
        }
    }

Answer 3

试试这个

 override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    DispatchQueue.main.async {
        self.player?.pause()
        self.playerLayer?.removeFromSuperlayer()
    }
}