.speak()

speak()

/// speak an utterance in `lang` language.
func speak(_ text: String, in lang: String = "en-GB") {
    // ⭐️ setup utterance
    let utterance = AVSpeechUtterance(string: text)
    utterance.voice = AVSpeechSynthesisVoice(language: lang)
    // ⭐️ speak utterance
    let synthesizer = AVSpeechSynthesizer()
    synthesizer.speak(utterance)
}

💈範例

SpeakButton

import SwiftUI
import AVFoundation

struct SpeakButton: View {
    let text: String
    let language: Language
    var body: some View {
        Button { speak() } label: { buttonLabel }
    }
}

extension SpeakButton {
    
    enum Language: String {
        case enGB = "en-GB"
        case enUS = "en-US"
        case zhTW = "zh-TW"
        case zhCN = "zh-CN"
        case zhHK = "zh-HK"
    }
    
    init(_ text:String, in lang: Language = .enGB) {
        self.text = text
        self.language = lang
    }
    
    static let synthesizer = AVSpeechSynthesizer()
    
    /// speak an utterance.
    func speak() {
        // setup utterance
        let utterance = AVSpeechUtterance(string: text)
        utterance.voice = AVSpeechSynthesisVoice(language: language.rawValue)
        // speak utterance
        SpeakButton.synthesizer.speak(utterance)
    }
    
    /// button label
    var buttonLabel: some View {
        Text(text)
            .fontWeight(.bold)
            .font(.system(.headline, design: .rounded))
            .padding()
            .padding(.horizontal, 8)
            .foregroundColor(.white)
            .background(Color.purple)
            .cornerRadius(8)
            .shadow(radius: 4)
    }
}

struct SpeakButton_Previews: PreviewProvider {
    static var previews: some View {
        VStack {
            SpeakButton("Hello, Swift")
            SpeakButton("May I help you?")
            SpeakButton("May I help you?", in: .enUS)
            SpeakButton("主人，今晚要來點什麼？", in: .zhTW)
            SpeakButton("主人，今晚要來點什麼？", in: .zhHK)
        }
    }
}

📗 參考

• Beginning iOS Programming with Swift and SwiftUI (iOS 15), p.101

• HwS ⟩ How to highlight text to speech words being read using AVSpeechSynthesizer

📘 手冊

• AVFoundation ⟩ Speech Synthesis ⟩

  • AVSpeechUtterance (class) - change the voice, pitchMultiplier, volume, rate, preUtteranceDelay, or postUtteranceDelay parameters for the utterance.

  • AVSpeechSynthesisVoice (class)

  • AVSpeechSynthesizer (class)

👥 相關

• Language Tags

• pitchMultiplier：講話的音調，範圍是 0.5 ~ 2 (預設 = 1)

• rate：講話的速度，範圍是 0 ~ 1

• volume：音量，範圍：0 ~ 1

• postUtteranceDelay：說完後的停頓時間

• preUtteranceDelay：說之前的停頓時間

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