操场上的 Swift AVFoundation 不输出声音

Posted 2023-02-25

【中文标题】操场上的 Swift AVFoundation 不输出声音

【英文标题】：Swift AVFoundation in playground not outputting sound

【发布时间】：2017-03-30 01:36:40

【问题描述】：

我的摩尔斯电码翻译器不会输出应有的声音。我已经在没有此功能的情况下测试了扬声器和我的方法，它可以完美运行，但它与程序的其余部分无关。编译器没有给我任何错误，操场也没有崩溃，它只是不播放声音。音量和铃声已满。

func speakTheCode(message: String) 
    var speaker = AVAudioPlayer()
    let longBeep = #fileLiteral(resourceName: "beep_long.mp3")
    let shortBeep = #fileLiteral(resourceName: "beep_short.mp3")
    let dash = "-"
    let dot = "."
    for character in message.characters 
        if character == dash[dash.startIndex] 
                speaker = try! AVAudioPlayer(contentsOf: longBeep)
                speaker.prepareToPlay()
            print("-")
        
        else if character == dot[dot.startIndex] 
                speaker = try! AVAudioPlayer(contentsOf: shortBeep)
                speaker.prepareToPlay()
                print(".")
        
        speaker.play()
    

我已经搞砸了好几个小时的代码，但没有任何效果。我做错了什么（如果有的话）？

【参考方案1】：

在一些游乐场播放音频时似乎存在问题。看到这个帖子：

Playing a sound in a Swift Playground

但是，我能够对您的代码进行一些更改并使其正常工作。这是我的代码：

class Morse:NSObject, AVAudioPlayerDelegate 
    private var message = ""
    private var dotSound:AVAudioPlayer!
    private var dashSound:AVAudioPlayer!
    private let dash = Character("-")
    private let dot = Character(".")
    private var index:String.Index!

    init(message:String) 
        super.init()
        do 
            if let url = Bundle.main.url(forResource:"beep_short", withExtension:"mp3") 
                self.dotSound = try AVAudioPlayer(contentsOf:url)
                self.dotSound.delegate = self
                self.dotSound.prepareToPlay()
            
         catch 
            NSLog("Error loading dot audio!")
        
        do 
            if let url = Bundle.main.url(forResource:"beep_long", withExtension:"mp3") 
                self.dashSound = try AVAudioPlayer(contentsOf:url)
                self.dashSound.delegate = self
                self.dashSound.prepareToPlay()
            
         catch 
            NSLog("Error loading dash audio!")
        
        self.message = message
        self.index = message.startIndex
    

    func playCharacter() 
        let character = message.characters[index]
        NSLog("Character: \(character)")
        if character == dash 
            dashSound.play()
         else if character == dot 
            dotSound.play()
        
    

    func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) 
        NSLog("Finished playing")
        if index != message.endIndex 
            self.index = message.index(after:index)
            playCharacter()
        
    


let m = Morse(message:"...---")
m.playCharacter()

PlaygroundPage.current.needsIndefiniteExecution = true

我必须启用无限期执行才能让代码完全执行。此外，我在加载第二个音频文件时遇到了一些问题，但我没有进一步调查是否是我的测试文件的问题或其他问题，因为它大部分都有效。

【参考方案2】：

@Fahim 仍然显示错误

类莫尔斯：NSObject，AVAudioPlayerDelegate 私人 var 消息 = "" 私人 var dotSound:AVAudioPlayer！ 私人 var dashSound:AVAudioPlayer！ 私人让破折号=字符（“-”） private let dot = Character(".") 私有变量索引：String.Index！

init(message:String) 
    super.init()
    do 
        if let url = Bundle.main.url(forResource:"beep_short", withExtension:"mp3") 
            self.dotSound = try AVAudioPlayer(contentsOf:url)
            self.dotSound.delegate = self
            self.dotSound.prepareToPlay()
        
     catch 
        NSLog("Error loading dot audio!")
    
    do 
        if let url = Bundle.main.url(forResource:"beep_long", withExtension:"mp3") 
            self.dashSound = try AVAudioPlayer(contentsOf:url)
            self.dashSound.delegate = self
            self.dashSound.prepareToPlay()
        
     catch 
        NSLog("Error loading dash audio!")
    
    self.message = message
    self.index = message.startIndex


func playCharacter() 
    let character = message.characters[index]
    NSLog("Character: \(character)")
    if character == dash 
        dashSound.play()
     else if character == dot 
        dotSound.play()
    


func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) 
    NSLog("Finished playing")
    if index != message.endIndex 
        self.index = message.index(after:index)
        playCharacter()
    

让 m = Morse(message:"...---") m.playCharacter()

PlaygroundPage.current.needsIndefiniteExecution = true

【讨论】：

当您将 cmets 作为官方答案发布时会令人困惑。你的这个“答案”应该是对 Fahim 答案的评论，你应该编辑你的问题以显示这个更新的代码。