AVSpeechSynthesizer isSpeaking在Swift中不起作用

问题描述

因此，在更新到Xcode 12.0.1之后，AVSpeechSynthesizer现在正在模拟器上工作（它已经一段时间没有为我工作了）。现在，无论合成器是否在讲话，isspeaking变量始终为false。我想根据合成器是否在讲话来触发我的看法的变化。下面的简单版本，有什么想法吗？

import SwiftUI
import AVFoundation

struct ContentView: View {

var synthesizer = AVSpeechSynthesizer()
var utterance = AVSpeechUtterance(string: "Hello World")

var body: some View {
    vstack {
        Text(synthesizer.isspeaking ? "Speaking" : "Not Speaking")
        Button(action: {synthesizer.speak(utterance)}) {
            Text("Speak To Me")
        }
    }
}
}

解决方法

在您的情况下，它不会被更新，因为synthesiser.isSpeaking在SwiftUI中是不可观察的。您必须使用视图模型类和委托回调来处理此状态更改

这是初始演示（您可以自己添加停止/暂停/继续操作）

class SpeachViewModel: NSObject,ObservableObject,AVSpeechSynthesizerDelegate {
    @Published var isSpeaking = false

    private var synthesizer = AVSpeechSynthesizer()
    override init() {
        super.init()
        synthesizer.delegate = self
    }

    deinit {
        synthesizer.delegate = nil
    }

    func speak(_ utterance: AVSpeechUtterance) {
        self.synthesizer.speak(utterance)
    }

    // MARK: AVSpeechSynthesizerDelegate
    internal func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer,didStart utterance: AVSpeechUtterance) {
        self.isSpeaking = true
    }

    internal func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer,didFinish utterance: AVSpeechUtterance) {
        self.isSpeaking = false
    }

    internal func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer,didPause utterance: AVSpeechUtterance) {
        self.isSpeaking = false
    }

    internal func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer,didCancel utterance: AVSpeechUtterance) {
        self.isSpeaking = false
    }

    internal func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer,didContinue utterance: AVSpeechUtterance) {
        self.isSpeaking = true
    }
}

struct ContentView: View {

    @ObservedObject var vm = SpeachViewModel()
    var utterance = AVSpeechUtterance(string: "Hello World")

    var body: some View {
        VStack {
            Text(vm.isSpeaking ? "Speaking" : "Not Speaking")
            Button(action: {vm.speak(utterance)}) {
                Text("Speak To Me")
            }
        }
    }
}