如何从本地文件播放音频？

Posted 2023-02-25

【中文标题】如何从本地文件播放音频？

【英文标题】：How to Play Audio from Local File?

【发布时间】：2019-03-13 18:23:23

【问题描述】：

我想播放下载的本地音频文件，但无法播放：

class AVPlayerService 
static let instance = AVPlayerService()

private var audioPlayer: AVPlayer!
public weak var delegate: AVPlayerServiceDelegate?

func setupPlayer(forURL url: URL) 
    let playerItem: AVPlayerItem = AVPlayerItem(url: URL(fileURLWithPath: "\(url)")
    audioPlayer = AVPlayer(playerItem: playerItem)
    audioPlayer.play() 

我在这里获取本地文件，然后在我的视图控制器中调用它：

func getDownloadedSurahFor(surah: Surah, reciter: Reciter) -> (Exists, URL?) 
    let documentsDirectoryURL =  FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!

    // lets create your destination file url
    let destinationUrl = documentsDirectoryURL.appendingPathComponent("\(reciter.name): \(surah.number)")
    print(destinationUrl)

    // to check if it exists before downloading it
    if FileManager.default.fileExists(atPath: destinationUrl.path) 
        print("Already downloaded")
        return (.exists, destinationUrl)
     else 
        return (.doesNotExist, nil)
    

在我的 Viewcontroller 中，我检查它是否存在，然后我调用 setupPlayer：

let (exists, url) =  DataService.instance.getDownloadedSurahFor(surah: playingSurah, reciter: reciter)
        if exists == .exists 
            self.audioservice.setupPlayer(forURL: url!)
            self.setupSlider()
            self.changeButtonTo(.pause)
            print("Downloaded file should now play")
        

【问题讨论】：

重复***.com/questions/54544067/…

@excitedmicrobe 不起作用

【参考方案1】：

简单适用于 Swift 4+ 的解决方案：

import Foundation
import AVFoundation

final class MediaPlayer 
    static var player = AVAudioPlayer()

    class func play() 
        do 
            let file = Bundle.main.url(forResource: "file_name", withExtension: "mp3")!
            player = try AVAudioPlayer(contentsOf: file)
            player.numberOfLoops = 0 // loop count, set -1 for infinite
            player.volume = 1
            player.prepareToPlay()

            try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: [])
            try AVAudioSession.sharedInstance().setActive(true)

            player.play()
         catch _ 
            print("catch")
        
    

对于 Swift 4+ 的多次使用：

import UIKit
import AudioToolbox

struct SoundPlayer 
    static var filename : String?
    static var enabled : Bool = true

    private struct Internal 
        static var cache = [URL:SystemSoundID]()
    

    static func playSound(soundFile: String) 
        if !enabled 
            return
        

        if let url = Bundle.main.url(forResource: soundFile, withExtension: nil) 
            var soundID : SystemSoundID = Internal.cache[url] ?? 0

            if soundID == 0 
                AudioServicesCreateSystemSoundID(url as CFURL, &soundID)
                Internal.cache[url] = soundID
            

            AudioServicesPlaySystemSound(soundID)
         else 
            print("Could not find sound file name `\(soundFile)`")
        
    

    // call the function with filename
    static func play(file: String) 
        self.playSound(soundFile: file)
    

查看此主题以了解 Swift 2 -> https://***.com/a/35000526/2125010

【参考方案2】：

只需要添加.mp3：

let destinationUrl = documentsDirectoryURL.appendingPathComponent("\(reciter.name): \(surah.number).mp3")

【讨论】：

小心。并非每个音频文件都在 mp3 中

就我而言是这样。 Bc 我正在使用云 Firestore 存储，我自己上传了文件