使用SFSpeechRecognizer后，AVSpeechSynthesizer不会说话
因此，我构建了一个使用SFSpeechRecognizer进行语音识别的简单应用程序，并在屏幕上的UITextView中将转换后的语音显示为文本。 现在我正试图让手机说出显示的文字。 它由于某种原因不起作用。 AVSpeechSynthesizer说function仅在使用SFSpeechRecognizer之前有效。 例如，当应用程序启动时，它会在UITextView中显示一些欢迎文本，如果我点按“说出”按钮，手机会说出欢迎文本。 然后，如果我进行录音（用于语音识别），识别的语音将显示在UITextView中。 现在我想让手机说出那个文字，但不幸的是它没有。
这是代码
import UIKit import Speech import AVFoundation class ViewController: UIViewController, SFSpeechRecognizerDelegate, AVSpeechSynthesizerDelegate { @IBOutlet weak var textView: UITextView! @IBOutlet weak var microphoneButton: UIButton! private let speechRecognizer = SFSpeechRecognizer(locale: Locale.init(identifier: "en-US"))! private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest? private var recognitionTask: SFSpeechRecognitionTask? private let audioEngine = AVAudioEngine() override func viewDidLoad() { super.viewDidLoad() microphoneButton.isEnabled = false speechRecognizer.delegate = self SFSpeechRecognizer.requestAuthorization { (authStatus) in var isButtonEnabled = false switch authStatus { case .authorized: isButtonEnabled = true case .denied: isButtonEnabled = false print("User denied access to speech recognition") case .restricted: isButtonEnabled = false print("Speech recognition restricted on this device") case .notDetermined: isButtonEnabled = false print("Speech recognition not yet authorized") } OperationQueue.main.addOperation() { self.microphoneButton.isEnabled = isButtonEnabled } } } @IBAction func speakTapped(_ sender: UIButton) { let string = self.textView.text let utterance = AVSpeechUtterance(string: string!) let synthesizer = AVSpeechSynthesizer() synthesizer.delegate = self synthesizer.speak(utterance) } @IBAction func microphoneTapped(_ sender: AnyObject) { if audioEngine.isRunning { audioEngine.stop() recognitionRequest?.endAudio() microphoneButton.isEnabled = false microphoneButton.setTitle("Start Recording", for: .normal) } else { startRecording() microphoneButton.setTitle("Stop Recording", for: .normal) } } func startRecording() { if recognitionTask != nil { //1 recognitionTask?.cancel() recognitionTask = nil } let audioSession = AVAudioSession.sharedInstance() //2 do { try audioSession.setCategory(AVAudioSessionCategoryRecord) try audioSession.setMode(AVAudioSessionModeMeasurement) try audioSession.setActive(true, with: .notifyOthersOnDeactivation) } catch { print("audioSession properties weren't set because of an error.") } recognitionRequest = SFSpeechAudioBufferRecognitionRequest() //3 guard let inputNode = audioEngine.inputNode else { fatalError("Audio engine has no input node") } //4 guard let recognitionRequest = recognitionRequest else { fatalError("Unable to create an SFSpeechAudioBufferRecognitionRequest object") } //5 recognitionRequest.shouldReportPartialResults = true //6 recognitionTask = speechRecognizer.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in //7 var isFinal = false //8 if result != nil { self.textView.text = result?.bestTranscription.formattedString //9 isFinal = (result?.isFinal)! } if error != nil || isFinal { //10 self.audioEngine.stop() inputNode.removeTap(onBus: 0) self.recognitionRequest = nil self.recognitionTask = nil self.microphoneButton.isEnabled = true } }) let recordingFormat = inputNode.outputFormat(forBus: 0) //11 inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, when) in self.recognitionRequest?.append(buffer) } audioEngine.prepare() //12 do { try audioEngine.start() } catch { print("audioEngine couldn't start because of an error.") } textView.text = "Say something, I'm listening!" } func speechRecognizer(_ speechRecognizer: SFSpeechRecognizer, availabilityDidChange available: Bool) { if available { microphoneButton.isEnabled = true } else { microphoneButton.isEnabled = false } } } 问题是，当您开始语音识别时，您已将音频会话类别设置为记录。 您无法使用Record的音频会话播放任何音频（包括语音合成）。
请使用以下代码解决问题：
let audioSession = AVAudioSession.sharedInstance() do { try audioSession.setCategory(AVAudioSessionCategoryPlayback) try audioSession.setMode(AVAudioSessionModeDefault) } catch { print("audioSession properties weren't set because of an error.") } Here, we have to use the above code in the following way: @IBAction func microphoneTapped(_ sender: AnyObject) { if audioEngine.isRunning { audioEngine.stop() recognitionRequest?.endAudio() let audioSession = AVAudioSession.sharedInstance() do { try audioSession.setCategory(AVAudioSessionCategoryPlayback) try audioSession.setMode(AVAudioSessionModeDefault) } catch { print("audioSession properties weren't set because of an error.") } microphoneButton.isEnabled = false microphoneButton.setTitle("Start Recording", for: .normal) } else { startRecording() microphoneButton.setTitle("Stop Recording", for: .normal) } }
这里，在停止audioengine之后，我们将audioSession 类别设置为AVAudioSessionCategoryPlayback ，将audioSession模式设置为AVAudioSessionModeDefault 。然后，当您调用下一个文本到语音方法时，它将正常工作。
您应该从以下位置更改startRecording方法的这一行：
try audioSession.setCategory(AVAudioSessionCategoryRecord)
至：
try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord)
尝试这个：
audioSession.setCategory(AVAudioSessionCategoryRecord)
使用STT时，你必须这样设置：
AVAudioSession *avAudioSession = [AVAudioSession sharedInstance]; if (avAudioSession) { [avAudioSession setCategory:AVAudioSessionCategoryRecord error:nil]; [avAudioSession setMode:AVAudioSessionModeMeasurement error:nil]; [avAudioSession setActive:true withOptions:AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation error:nil]; }
当使用TTS再次设置AudioSession时，如下所示：
[regRequest endAudio]; AVAudioSession *avAudioSession = [AVAudioSession sharedInstance]; if (avAudioSession) { [avAudioSession setCategory:AVAudioSessionCategoryPlayback error:nil]; [avAudioSession setMode:AVAudioSessionModeDefault error:nil]; }
它的工作对我来说很完美。 LOW AUDIO问题也解决了。