如何在 AVAudioPlayer 开始播放音频时准确获取通知？

Posted 2023-02-25

【中文标题】如何在 AVAudioPlayer 开始播放音频时准确获取通知？

【英文标题】：How to get notification exactly when AVAudioPlayer starts playing audio?

【发布时间】：2019-05-07 09:49:45

【问题描述】：

注意：在将其标记为重复之前，请仔细阅读标题（和问题）。问题是关于AVAudioPlayer 而不是AVPlayer。

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所以根据AVAudioPlayer的文档

open func play() -> Bool /* sound is played asynchronously. */

我需要在音频开始时准确地向用户显示一个弹出窗口。这不是我们打电话给play()的时候。

当播放器停止播放但没有开始播放时，有一个委托调用:(。

我找不到任何方法来准确知道音频何时开始。有什么方法可以检查吗？

【问题讨论】：

if self.avPlayer?.currentItem?.status == AVPlayerItem.Status.readyToPlay if (self.player?.currentItem?.isPlaybackLikelyToKeepUp) == true // 你可以在这里管理

@Mr.Ahtazaz 请仔细阅读标题。它不是 AVPlayer，它是 AVAudioPlayer。

@Sh_Khan AVPlayer 和 AVAudioPlayer 是两个不相关的类

@iur 您可以先尝试将观察者放在属性上，例如 currentTime

@mag_zbc 我也考虑过。在文档中有一个关于playing 属性Important. Do not poll this property to determine when playback has completed, instead implement the specified delegate method. 的注释，所以我不确定我们是否可以使用它来检查播放器是否开始播放。

【参考方案1】：

我也面临同样的问题，只是决定创建一个基于 AVPlayer 的新类：

import AVFoundation
import UIKit

 class AudioManager 

    private init() 

    public static let shared = AudioManager()

    var player: AVPlayer?
    var item: AVPlayerItem?
    var layer: AVPlayerLayer?
    var currentUrl: URL?

    var pauseTime: CMTime?
    var endOfTrackObserver: Any?

    func startPlayContentOf(url: URL?) 

        NotificationCenter.default.addObserver(self,
                                               selector: #selector(self.playerItemDidReachEnd(notification:)),
                                               name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
                                               object: self.player?.currentItem)

        guard let newAudioUrl = url else  return 
        let newAudioItem = AVPlayerItem(url: newAudioUrl)


        if let currentUrl = self.currentUrl, currentUrl == newAudioUrl 
            //same track
            if let playing = self.player?.isPlaying, playing == true  
                self.pauseTime = self.player?.currentTime()
                self.pause()
             else 
                self.player = AVPlayer(playerItem: newAudioItem)
                self.player?.volume = 3
                self.player?.seek(to: self.pauseTime ?? CMTime.zero)
                self.layer = AVPlayerLayer(player: self.player)
                self.layer?.frame = CGRect(x: 0, y: 0, width: 10, height: 10)
                self.layer?.backgroundColor = UIColor.clear.cgColor
                guard let layer = self.layer else  return 
                UIApplication.shared.keyWindow?.rootViewController?.view.layer.insertSublayer(layer, at: 0)
                self.play()
            
         else 
            //new track
            self.pauseTime = nil
            self.pause()
            self.player = AVPlayer(playerItem: newAudioItem)
            self.player?.volume = 3
            self.layer = AVPlayerLayer(player: self.player)
            self.layer?.frame = CGRect(x: 0, y: 0, width: 10, height: 10)
            self.layer?.backgroundColor = UIColor.clear.cgColor
            guard let layer = self.layer else  return 
            UIApplication.shared.keyWindow?.rootViewController?.view.layer.insertSublayer(layer, at: 0)
            self.play()
        

        self.currentUrl = newAudioUrl
    

    func playOrPause() 
        guard self.player != nil else  return 
        if self.player!.isPlaying 
            self.player!.pause()
         else 
            self.player?.replaceCurrentItem(with: self.item)
            self.player!.play()
        
    

    func pause() 
        guard self.player != nil else  return 
        self.player!.pause()
    

    func play() 
        guard self.player != nil else  return 
        self.player!.play()
    

    @objc func playerItemDidReachEnd(notification: Notification) 
        self.pauseTime = nil