Swift AVPlayer的使用

AVPlayer存在于AVFoundation中，它更加接近于底层，可以进行自定义，所以也更加灵活。AVPlayer本身并不能显示视频，而且它也不像MPMoviePlayerController有一个view属性。如果AVPlayer要显示必须创建一个播放器层AVPlayerLayer用于展示，播放器层继承于CALayer，有了AVPlayerLayer之添加到控制器视图的layer中即可。
最近实现一个基本的AVPlayer播放器，代码如下：

自定义一个View，播放器的UI部分主要在这里实现

<pre>import UIKit
import AVFoundation

protocol WXPlayerViewDelegate: NSObjectProtocol {

func wxplayer(playerView: WXPlayerView,slider: UISlider)
func wxplayer(playerView:WXPlayerView,playAndPause playBtn:UIButton)

}

class WXPlayerView: UIView {

var playerLayer: AVPlayerLayer!
var timeLabel: UILabel!
var slider: UISlider!
var progressView:UIProgressView!
var playBtn:UIButton!
var sliding = false
var playing = true
weak var delegate: WXPlayerViewDelegate?
init(){

    super.init(frame: CGRect.zero)
    self.initView()
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func initView()
{
    self.playerLayer = AVPlayerLayer()
    self.layer.addSublayer( self.playerLayer)
    
    self.timeLabel = UILabel()

// self.timeLabel.backgroundColor = UIColor.red
self.timeLabel.textColor = UIColor.white
self.timeLabel.font = UIFont.systemFont(ofSize: 14)
self.addSubview(self.timeLabel)

    self.slider = UISlider()
    self.addSubview(self.slider)
    
    self.slider.minimumValue = 0
    self.slider.maximumValue = 1
    self.slider.value = 0
    self.slider.maximumTrackTintColor = UIColor.clear
    self.slider.minimumTrackTintColor = UIColor.white
    self.slider.setThumbImage(UIImage(named:"ic_shipinjindu_nor"), for: .normal)
    
    // 按下的时候
    self.slider.addTarget(self, action: #selector(self.sliderTouchDown), for: .touchDown)
  
    // 弹起的时候
     self.slider.addTarget(self, action: #selector(self.sliderTouchUpOut), for: .touchUpOutside)
     self.slider.addTarget(self, action: #selector(self.sliderTouchUpOut), for: .touchUpInside)
     self.slider.addTarget(self, action: #selector(self.sliderTouchUpOut), for: .touchCancel)
    
    self.progressView = UIProgressView()
    self.progressView.backgroundColor = UIColor.lightGray
    self.insertSubview(self.progressView, belowSubview: self.slider)
    self.progressView.tintColor = UIColor.red
    self.progressView.progress = 0
    
    self.playBtn = UIButton()
    self.playBtn.setImage(UIImage(named:"videopause_control_nor"), for: .normal)
    self.addSubview(self.playBtn)
    self.playBtn.addTarget(self, action: #selector(self.playBtnAction), for: .touchUpInside)
}

func sliderTouchDown(){
    self.sliding = true
}
func sliderTouchUpOut(){
    // 代理处理
    delegate?.wxplayer(playerView: self, slider: self.slider)
}

func updateUI(timeStr: String) {
    
    self.timeLabel.text = timeStr
    self.timeLabel.sizeToFit()
    self.setNeedsLayout()
}
func playBtnAction()
{
    self.playing = !self.playing // 改变状态
    
    // 根据状态设定图片
    if playing {
        playBtn.setImage(UIImage(named: "videopause_control_nor"), for: .normal)
    }else{
        playBtn.setImage(UIImage(named: "videoplay_control_nor"), for: .normal)
    }
    // 代理方法
    delegate?.wxplayer(playerView: self, playAndPause: self.playBtn)
}

override func layoutSubviews() {
    super.layoutSubviews()
    
    self.playerLayer.frame = self.bounds
    self.timeLabel.frame.origin.x = self.frame.width - self.timeLabel.frame.width - 5
    self.timeLabel.frame.origin.y = self.frame.height - self.timeLabel.frame.height - 50
    
    self.slider.frame.origin.x = 40
    self.slider.frame.origin.y = self.frame.height - 75
    self.slider.frame.size.width = self.frame.width - 140
    
    self.progressView.frame.origin.x = 42
    self.progressView.frame.origin.y = self.frame.height - 59
    self.progressView.frame.size.width =  self.frame.width - 142
    
    self.playBtn.frame = CGRect(x: 5, y: self.frame.height - 75, width: 30, height: 30)
}

}
</pre>

接下来是VC中的代码，主要是实现逻辑部分

<pre>import UIKit
import AVFoundation

extension ViewController: WXPlayerViewDelegate{

func wxplayer(playerView: WXPlayerView, slider: UISlider) {
    
    if self.avplayer.status == AVPlayerStatus.readyToPlay{
    
         let duration = slider.value * Float(CMTimeGetSeconds(self.avplayer.currentItem!.duration))
        let seekTime = CMTimeMake(Int64(duration), 1)
        self.avplayer.seek(to: seekTime, completionHandler: { (b) in
            
            playerView.sliding = false
        })
    }
}

func wxplayer(playerView: WXPlayerView, playAndPause playBtn: UIButton) {
    
    if !playerView.playing{
        self.avplayer.pause()
    }else{
        if self.avplayer.status == AVPlayerStatus.readyToPlay{
            self.avplayer.play()
        }
    }
}

}

class ViewController: UIViewController {
var playerView: WXPlayerView!
var playerItem: AVPlayerItem!
var avplayer: AVPlayer!
var playerLayer: AVPlayerLayer!
var link: CADisplayLink!

override func viewDidLoad() {
    super.viewDidLoad()
   
    self.initPlayer()
    self.link = CADisplayLink(target: self, selector: #selector(self.update))
    self.link.add(to: .main, forMode: RunLoopMode.defaultRunLoopMode)
}

deinit {
    
    self.playerItem.removeObserver(self, forKeyPath: "loadedTimeRanges")
    self.playerItem.removeObserver(self, forKeyPath: "status")
}

func initPlayer()
{
    let url = URL(string: "http://vt1.doubanio.com/201609291737/4af83e686c0432c0dbd3c320f14eba6f/view/movie/M/302030039.mp4")
    self.playerItem = AVPlayerItem(url: url!)
    self.playerItem.addObserver(self, forKeyPath: "loadedTimeRanges", options: .new, context: nil)
    self.playerItem.addObserver(self, forKeyPath: "status", options: .new, context: nil)
    self.avplayer = AVPlayer(playerItem: self.playerItem)
    self.playerLayer = AVPlayerLayer(player: self.avplayer)
    self.playerLayer.videoGravity = AVLayerVideoGravityResizeAspect
    self.playerLayer.contentsScale = UIScreen.main.scale
    self.view.layer.addSublayer( self.playerLayer)
    
    self.playerView = WXPlayerView()
    self.playerView.delegate = self
    self.playerView.frame = CGRect(x: 0, y: 20, width: self.view.frame.width, height: 300)
    self.view.addSubview(self.playerView)
    self.playerView.playerLayer = self.playerLayer
    self.playerView.layer.insertSublayer(self.playerLayer, at: 0)
}

func update(){
    
    //暂停的时候
    if !self.playerView.playing{
        return
    }
    
    let currentTime = CMTimeGetSeconds(self.avplayer.currentTime())
    let totalTime = TimeInterval(self.playerItem.duration.value) / TimeInterval(self.playerItem.duration.timescale)
    let timeStr = "\(self.formatPlayTime(secounds: currentTime))/\(self.formatPlayTime(secounds: totalTime))"
    self.playerView.updateUI(timeStr: timeStr)
    if !self.playerView.sliding{
        // 播放进度
        self.playerView.slider.value = Float(currentTime/totalTime)
    }
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    
    if keyPath == "loadedTimeRanges"{
    
        // 通过监听AVPlayerItem的"loadedTimeRanges"，可以实时知道当前视频的进度缓冲
        let loadedTime = avalableDurationWithplayerItem()
        let totalTime = CMTimeGetSeconds(playerItem.duration)
        let percent = loadedTime/totalTime // 计算出比例
        // 改变进度条
        self.playerView.progressView.progress = Float(percent)
    
    }else if keyPath == "status"{
    
        if self.playerItem.status == AVPlayerItemStatus.readyToPlay{
            
            self.avplayer.play()

        }else
        {
            print("加载异常")
        }
    }
}

func formatPlayTime(secounds: TimeInterval) -> String{
    if secounds.isNaN{
        
        return "00:00"
    }

    let min = Int(secounds / 60)
    let sec = Int(secounds.truncatingRemainder(dividingBy: 60) )
    return String(format: "%02d:%02d", min,sec)
}
// 计算当前缓冲进度
func avalableDurationWithplayerItem() -> TimeInterval{

    guard let loadedTimeRanges = self.avplayer.currentItem?.loadedTimeRanges,let first = loadedTimeRanges.first else {fatalError()}
    let timeRange = first.timeRangeValue
    let startSeconds = CMTimeGetSeconds(timeRange.start)
    let durationSecound = CMTimeGetSeconds(timeRange.duration)
    let result = startSeconds + durationSecound
    return result
}

}
</pre>
实现后的效果图

1.png