AVSpeechSynthesizer is Speaking在Swift中不起作用

Question

所以在更新到Xcode 12.0.1之后，AVSpeechSynthesizer现在正在模拟器上工作(它已经有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说话来触发我的观点的改变。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")
}
}
}
}

Answer 1

在您的案例中，它只是没有更新，因为synthesiser.isSpeaking对于SwiftUI是不可观察的。您必须使用视图模型类和委托回调来处理这种状态更改

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")
}
}
}
}