问在语音框架ios 10上继续转换时出现崩溃

EN

func startRecording(){

    if recognizationTask != nil{
        recognizationTask?.cancel()
        recognizationTask = nil
    }

    let audioSession = AVAudioSession.sharedInstance()
    do{
        try audioSession.setCategory(AVAudioSessionCategoryRecord)
        try audioSession.setMode(AVAudioSessionModeSpokenAudio)
        try audioSession.setActive(true, with: .notifyOthersOnDeactivation)
    } catch {
        print("Audion session properies weren't set because of an error.")
    }

    recognizationRequest = SFSpeechAudioBufferRecognitionRequest()

    guard let inputNode = audioEngine.inputNode as AVAudioInputNode? else {
        fatalError("Audio engine has no input node")
    }

    guard let recognizationRequest = recognizationRequest else {
        fatalError("Unable to create an SFSpeechAudioBufferRecognizationRequest object.")
    }

    recognizationRequest.shouldReportPartialResults = true

    recognizationTask = speechRecognizer?.recognitionTask(with: recognizationRequest, resultHandler: { (result, error) in
        var isFinal = false

        if result != nil{
            self.txtViewSiriDetecation.text = result?.bestTranscription.formattedString
            isFinal = (result?.isFinal)!
        }

        if error != nil || isFinal {
            self.audioEngine.stop()
            inputNode.removeTap(onBus:0)

            self.recognizationRequest = nil
            self.recognizationTask = nil

            self.btnSiri.isEnabled = true

        }


    })

    let recordingFormat = inputNode.outputFormat(forBus: 0)
    inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, when) in
        self.recognizationRequest?.append(buffer)
    }

    audioEngine.prepare()

    do {
        try audioEngine.start()
    } catch {
        print("audio engine couldn't start b'cus of an error.")
    }

    txtViewSiriDetecation.text = "Say something, I'm listening!"

}