Swift iOS - 当应用程序从后台返回时，AVPlayer 视频冻结暂停

在Swift iOS开发中，当我们的应用程序从后台返回到前台时，经常会遇到AVPlayer视频冻结或暂停的问题。这个问题可能会对用户体验产生负面影响，因此我们需要找到解决办法来确保视频在返回到前台时能够继续播放。

swift
override func viewDidLoad() {
    super.viewDidLoad()
    
    NotificationCenter.default.addObserver(self, selector: #selector(appDidBecomeActive), name: UIApplication.didBecomeActiveNotification, object: nil)
}

swift
@objc func appDidBecomeActive() {
    // 判断当前是否正在播放视频
    if player.rate == 0 {
        // 如果视频已经暂停，则重新播放
        player.play()
    }
}

swift
deinit {
    NotificationCenter.default.removeObserver(self)
}

swift
import UIKit
import AVFoundation
class ViewController: UIViewController {
    
    var player: AVPlayer!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 初始化AVPlayer
        let videoURL = Bundle.main.url(forResource: "video", withExtension: "mp4")
        player = AVPlayer(url: videoURL!)
        
        // 创建AVPlayerLayer来显示视频
        let playerLayer = AVPlayerLayer(player: player)
        playerLayer.frame = view.bounds
        view.layer.addSublayer(playerLayer)
        
        // 注册通知
        NotificationCenter.default.addObserver(self, selector: #selector(appDidBecomeActive), name: UIApplication.didBecomeActiveNotification, object: nil)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        // 开始播放视频
        player.play()
    }
    
    @objc func appDidBecomeActive() {
        // 判断当前是否正在播放视频
        if player.rate == 0 {
            // 如果视频已经暂停，则重新播放
            player.play()
        }
    }
    
    deinit {
        // 移除通知的观察者
        NotificationCenter.default.removeObserver(self)
    }
}