AVPlayer代码解析

import UIKit
import AVFoundation

class PlayerViewController: UIViewController {
    
    @IBOutlet weak var playButton: UIButton!
    
    @IBOutlet weak var finishView: UIView!
    
    @IBOutlet weak var backButton: UIButton!
    
    @IBOutlet weak var bottomView: UIView!
    
    @IBOutlet weak var slider: UISlider!
    
    @IBOutlet weak var timeLabel: UILabel!
    
    @IBOutlet weak var bottomConatraint: NSLayoutConstraint!
    
    @IBOutlet weak var topConatraint: NSLayoutConstraint!
    //MARK: - 属性
    //播放路径
    var playUrlStr = ""
    //播放状态
    var isPlaying = true
    //是否已经加载成功
    var isLoadFinish = false
    
    
    //播放器
    lazy var player:AVPlayer = {
    
        //创建播放源
        let item = AVPlayerItem.init(URL: NSURL.init(string: self.playUrlStr)!)
        //print("播放源\(self.playUrlStr)")
        //创建播放器
        let tplayer = AVPlayer.init(playerItem: item)
        
        //添加观察者观察播放源中loadedTimeRanges属性的值的改变
        //给指定对象的指定属性添加观察者，观察对象属性的值的改变
        //（想要观察哪个对象的属性，就用哪个对象去调用addObserver方法），所有继承自NSOject的类都有addObserver方法
        //参数1:观察者(谁去观察对象的属性的改变)
        //参数2:对象的属性地址 person.name -> name对应的keyPath就是("name"),person.car.color,->color对应keypath就是("car.color")
        //参数3:当值发生改变的时候，观察者需要获取的值的类型(旧值/新值)
        //参数4:上下文(nil)
        item.addObserver(self, forKeyPath: "loadedTimeRanges", options: .New, context: nil)
    
        //获取播放结束的时刻
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "endPlayAction", name: AVPlayerItemDidPlayToEndTimeNotification, object: nil)
    
        return tplayer
    }()
    
    
    //MARK: - 生命周期
    override func viewDidLoad() {
        super.viewDidLoad()

        //创建播放界面
        self.creatPlayerLayer()
        //开始播放
        self.player.play()
        
        
        //获取播放进度
        self.getPlayProgress()
        
    }//函数结束

}

//MARK: - 观察者
extension PlayerViewController{

    //当观察者观察的对象的属性的值发生改变后会自动调用的方法
    //参数1:被观察的属性的路径
    //参数2:被观察的对象
    //参数3:变化的值（旧值/新值)
    override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer) {
        
        //获取当前播放源的总时间
        let duraction = self.player.currentItem?.duration
        let totalTime = Float(duraction!.value) / Float(duraction!.timescale)
        
        //获取当前的缓存时间
        //1.获取播放源对象
        let item = object as! AVPlayerItem
        //2.获取缓存进度对象
        let value = item.loadedTimeRanges.first
        let timeRange = value?.CMTimeRangeValue
        //3.获取当前缓存到的时间
        let current = timeRange?.duration
        let currentTime = Float((current?.value)!) / Float((current?.timescale)!)
        print(currentTime)
        if currentTime > 1 {
            self.isLoadFinish = true
        }
        
    }
}

//MARK: - 播放功能相关
extension PlayerViewController{
    
    func endPlayAction() {
        
        //1.改变按钮的显示状态
        self.playButton.setImage(UIImage.init(named: "page_play_normal.png"), forState: .Normal)
        self.isPlaying = false
        //2.显示提示信息
        self.finishView.hidden = false
    }

    func getPlayProgress(){
        
        //获取播放进度
        self.player.addPeriodicTimeObserverForInterval(CMTimeMake(1, 1), queue: dispatch_get_global_queue(0, 0)) { (currentTime) in
            
            //1.计算时间(秒)
            //当前时间
            let current = CGFloat(currentTime.value) / CGFloat(currentTime.timescale)
            let currentStr = ToolManager.transformTime(current)
            //总时间
            let duraction = CGFloat((self.player.currentItem?.duration.value)!) / CGFloat((self.player.currentItem?.duration.timescale)!)
            let duractionStr = ToolManager.transformTime(duraction)
            //2.计算进度
            let progress = current/duraction
            //回到主线程刷新数据
            dispatch_async(dispatch_get_main_queue(), {
                
                self.timeLabel.text = "\(currentStr) / \(duractionStr)"
                self.slider.value = Float(progress)
            })
            
        }
    }
}

//MARK: - 界面相关
extension PlayerViewController{

    func creatPlayerLayer(){
        
        //创建layer
        let playLayer = AVPlayerLayer.init(player: self.player)
        playLayer.frame = self.view.bounds
        self.view.layer.addSublayer(playLayer)
        
        //改变层次
        self.view.bringSubviewToFront(self.backButton)
        self.view.bringSubviewToFront(self.bottomView)
        self.view.bringSubviewToFront(self.finishView)
        
    }
}

//MARK: - 按钮点击
extension PlayerViewController{
    
    override func touchesBegan(touches: Set, withEvent event: UIEvent?) {
        if bottomConatraint.constant == 0 {
            
            UIView.animateWithDuration(0.3, animations: { 
                
                self.bottomConatraint.constant = -50
                self.topConatraint.constant = -50
                self.view.layoutIfNeeded()
            })
        }else{
        
            UIView.animateWithDuration(0.3, animations: {
                
                self.bottomConatraint.constant = 0
                self.topConatraint.constant = 10
                self.view.layoutIfNeeded()
            })
        }
    }
    
    
    @IBAction func playAction2(sender: AnyObject) {
        
        //重新播放
        self.slider.value = 0
        self.playButton.setImage(UIImage.init(named: "pauseBtn.png"), forState: .Normal)
        self.isPlaying = true
        self.finishView.hidden = true
        
        self.player.seekToTime(CMTimeMake(0, 10))
        self.player.play()
    }
    
    @IBAction func sliderAction(sender: UISlider) {
        
        //先判断当前视频是否已经加载成功
        if self.isLoadFinish == false {
            
            sender.value = 0
            return
        }
        
        //拿到进度值
        let progress = slider.value
        
        //获取总的时间(秒)
        let time = Float((self.player.currentItem?.duration.value)!) / Float((self.player.currentItem?.duration.timescale)!)
        //计算当前时间
        let current = Int64(time*progress)
        
        //设置进度
        self.player.seekToTime(CMTimeMake(current, 1))
        
        
    }
    //播放/暂停
    @IBAction func playAction(sender: UIButton) {
        
        //如果正在播放
        if self.isPlaying{
            //暂停播放
            self.player.pause()
            self.isPlaying = false
            //改变按钮的显示状态
            sender.setImage(UIImage.init(named: "page_play_normal.png"), forState: .Normal)
        }else{
        
            //开始播放
            self.player.play()
            self.isPlaying = true
            //改变按钮的显示状态
            sender.setImage(UIImage.init(named: "pauseBtn.png"), forState: .Normal)
        }
    }
    
    //返回
    @IBAction func backAction(sender: UIButton) {
        
        //1.停止播放
        self.player.pause()
        //2.移除观察者
        //移除self对播放源中loadedTimeRanges的观察
        self.player.currentItem?.removeObserver(self, forKeyPath: "loadedTimeRanges")
        
        
        self.dismissViewControllerAnimated(true, completion: nil)
    }
    
}

//MARK: - 横屏相关
extension PlayerViewController{

    //是否支持屏幕旋转
    override func shouldAutorotate() -> Bool {
        return true
    }
    
    //设置屏幕的方向
    override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
        
        //横屏，home键在右
        return .LandscapeRight
    }
    
}