iOS视频播放&画中画

//
//  ViewController.swift
//  Palyer
//
//  Created by HuangZhen on 2021/8/20.
//

import UIKit
import AVKit

class ViewController: UIViewController, AVPlayerViewControllerDelegate {
    
    var playerItem: AVPlayerItem?
    var playerController: AVPlayerViewController!
    var picVC : AVPictureInPictureController!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        guard let url = URL(string: "https://xxxxx.mp4") else {
            return
        }
        playerController = AVPlayerViewController()
        playerController.showsPlaybackControls = true
        playerController.allowsPictureInPicturePlayback = true
//        if #available(iOS 14.2, *) {
//            playerController.canStartPictureInPictureAutomaticallyFromInline = true
//        } else {
//            // Fallback on earlier versions
//        }
        playerController.delegate = self
        
        playerItem = AVPlayerItem(url: url)
        playerItem?.automaticallyPreservesTimeOffsetFromLive = true
        playerController.player = AVPlayer(playerItem: playerItem)
        playerController.videoGravity = .resizeAspectFill
        playerController.view.frame = CGRect(x: 0, y: 100, width: view.frame.width, height: 300)
        view.addSubview(playerController.view)
        
        
        // 监听loadedTimeRanges属性来监听缓冲进度更新
        playerItem?.addObserver(self,
                                forKeyPath: "loadedTimeRanges",
                                options: .new,
                                context: nil)
        // 监听status属性进行播放
        playerItem?.addObserver(self,
                                forKeyPath: "status",
                                options: .new,
                                context: nil)
        
        if AVPictureInPictureController.isPictureInPictureSupported() {
            try! AVAudioSession.sharedInstance().setCategory(.playback)
        }
    }
    
    override func observeValue(forKeyPath keyPath: String?,
                                  of object: Any?,
                                  change: [NSKeyValueChangeKey : Any]?,
                                  context: UnsafeMutableRawPointer?) {
           guard let object = object as? AVPlayerItem  else { return }
           guard let keyPath = keyPath else { return }
           if keyPath == "status" {
               if object.status == .readyToPlay { //当资源准备好播放，那么开始播放视频
                   playerController?.player?.play()
                   print("正在播放...，视频总长度:\(formatPlayTime(seconds: CMTimeGetSeconds(object.duration)))")
               } else if object.status == .failed || object.status == .unknown {
                   print("播放出错")
               }
           } else if keyPath == "loadedTimeRanges" {
               let loadedTime = availableDurationWithplayerItem()
               print("当前加载进度\(loadedTime)")
           }
     }

     // 将秒转成时间字符串的方法，因为我们将得到秒。
     func formatPlayTime(seconds: Float64) -> String {
         let min = Int(seconds / 60)
         let sec = Int(seconds.truncatingRemainder(dividingBy: 60))
         return String(format: "%02d:%02d", min, sec)
     }

     // 计算当前的缓冲进度
     func availableDurationWithplayerItem() -> TimeInterval {
         guard let loadedTimeRanges = playerController.player?.currentItem?.loadedTimeRanges,
             let first = loadedTimeRanges.first else {
                  fatalError()
          }
         let timeRange = first.timeRangeValue
         let startSeconds = CMTimeGetSeconds(timeRange.start) // 本次缓冲起始时间
         let durationSecound = CMTimeGetSeconds(timeRange.duration)// 缓冲时间
         let result = startSeconds + durationSecound// 缓冲总长度
         return result
     }
}