操场上的 Swift AVFoundation 不输出声音

Question

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）？

Answer 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。

Answer 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