ios - 如何知道 AVSpeechUtterance 何时结束，以便继续应用事件？

Question

当 AVSpeechUtterance 正在说话时，我想等到它完成后再做其他事情。

AVSpeechSynthesizer 的一个属性似乎指示语音何时发生:

isSpeaking

尽管这个问题听起来既愚蠢又简单，但我想知道如何使用/检查此属性以等到语音结束后再继续？

或者:

有一个代表，我也不知道如何使用，它有能力在话语结束时做某事:

AVSpeechSynthesizerDelegate

有一个答案，here , 那就是说要用这个。但这对我没有帮助，因为我不知道如何使用委托(delegate)。

更新:

这是我设置口语课的方式:

import AVFoundation

class CanSpeak: NSObject, AVSpeechSynthesizerDelegate {

    let voices = AVSpeechSynthesisVoice.speechVoices()
    let voiceSynth = AVSpeechSynthesizer()
    var voiceToUse: AVSpeechSynthesisVoice?

    override init(){
        voiceToUse = AVSpeechSynthesisVoice.speechVoices().filter({ $0.name == "Karen" }).first
    }

    func sayThis(_ phrase: String){
        let utterance = AVSpeechUtterance(string: phrase)
        utterance.voice = voiceToUse
        utterance.rate = 0.5
        voiceSynth.speak(utterance)
    }
}

更新 2:错误的解决方法...

在 gameScene 中使用上面提到的 isSpeaking 属性:

voice.sayThis(targetsToSay)

    let initialPause = SKAction.wait(forDuration: 1.0)
    let holdWhileSpeaking = SKAction.run {
        while self.voice.voiceSynth.isSpeaking {print("STILL SPEAKING!")}
    }
    let pauseAfterSpeaking = SKAction.wait(forDuration: 0.5)
    let doneSpeaking = SKAction.run {print("TIME TO GET ON WITH IT!!!")}

run(SKAction.sequence(
    [   initialPause,
        holdWhileSpeaking,
        pauseAfterSpeaking,
        doneSpeaking
    ]))

Answer 1

委托(delegate)模式是面向对象编程中最常用的设计模式之一，它并不像看起来那么难。对于您的情况，您可以简单地让您的类(class)(游戏场景)成为 CanSpeak 类(class)的代表。

protocol CanSpeakDelegate {
   func speechDidFinish()
}

接下来将 AVSpeechSynthesizerDelegate 设置为您的 CanSpeak 类，声明 CanSpeakDelegate，然后使用 AVSpeechSynthesizerDelegate 委托(delegate)函数。

class CanSpeak: NSObject, AVSpeechSynthesizerDelegate {

   let voices = AVSpeechSynthesisVoice.speechVoices()
   let voiceSynth = AVSpeechSynthesizer()
   var voiceToUse: AVSpeechSynthesisVoice?

   var delegate: CanSpeakDelegate!

   override init(){
      voiceToUse = AVSpeechSynthesisVoice.speechVoices().filter({ $0.name == "Karen" }).first
      self.voiceSynth.delegate = self
   }

   func sayThis(_ phrase: String){
      let utterance = AVSpeechUtterance(string: phrase)
      utterance.voice = voiceToUse
      utterance.rate = 0.5
      voiceSynth.speak(utterance)
   }

   func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) {
      self.delegate.speechDidFinish()
   }
}

最后，在您的游戏场景类中，只需符合 CanSpeakDelegate 并将其设置为您的 CanSpeak 类的委托(delegate)。

class GameScene: NSObject, CanSpeakDelegate {

   let canSpeak = CanSpeak()

   override init() {
      self.canSpeak.delegate = self
   }

   // This function will be called every time a speech finishes
   func speechDidFinish() {
      // Do something
   }
}