음성 인식 후 마이크 색깔이 변하지 않아요.

안녕하세요.

강의를 보면서 쭈욱 진행하고 있는데, 에뮬레이터에서 음성인식을 테스트하면 음성인식이 완료되었음에도 마이크 색깔이 검정색으로 변하지 않습니다. 강의 내용대로 코드를 쳤는데 확인 부탁드립니다. (혹시 소스코드가 깃헙에는 없나요?..)

import 'package:dash_chat_2/dash_chat_2.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
import 'package:speech_to_text/speech_to_text.dart';
import 'package:speech_to_text/speech_recognition_result.dart';


class BasicScreen extends StatefulWidget {
  @override
  _BasicState createState() => _BasicState();
}

class _BasicState extends State<BasicScreen> {

  bool isListening = false;
  SpeechToText _speechToText = SpeechToText();
  bool _speechEnabled = false;
  String _lastWords = '';

  @override
  void initState() {
    super.initState();
    _initSpeech();
  }

  ChatUser user1 = ChatUser(
    id: '1',
    firstName: 'me',
    lastName: 'me',
  );

  ChatUser user2 = ChatUser(
    id: '2',
    firstName: 'chatGPT',
    lastName: 'openAI',
    profileImage: "assets/img/gpt_icon.png"
  );

  late List<ChatMessage> messages = <ChatMessage>[
    ChatMessage(
      text: '반갑습니다. 어서오세요. 무엇을 도와드릴까요?',
      user: user2,
      createdAt: DateTime.now(),
    ),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Basic example'),
      ),
      body: DashChat(
        currentUser: user1,
        onSend: (ChatMessage m) {
          setState(() {
            messages.insert(0, m);
          });
          Future<String> data = sendMessageToServer(m.text);
          data.then((value){
            setState(() {
              messages.insert(0, ChatMessage(
                text: value,
                user: user2, 
                createdAt: DateTime.now(),
                ));
            });
          });
        },
        messages: messages,
        inputOptions: InputOptions(
          leading: [
            IconButton(
              icon: Icon(Icons.mic, color: isListening? Colors.red: Colors.black),
              onPressed: (){
                setState(() {
                  isListening = !isListening;
                  if (isListening == true){
                    print('음성인식 시작');
                    _startListening();
                  }else{
                    print('음성인식 끝');
                    _stopListening();
                  }
                });
              },
            )
          ]
          ) ,
      ),
    );
  }

  Future<String> sendMessageToServer(String message) async{

    var headers = {
      'Content-Type': 'application/json',
      'Authorization': 'Bearer sk-proj-b2yCBjZ7jwkR7nmWl4NLT3BlbkFJmm0iaZMBGPJHHy3b3I4J',
    };
    var request = http.Request('POST', Uri.parse('https://api.openai.com/v1/chat/completions'));
    request.body = json.encode({
      "model": "gpt-3.5-turbo",
      "messages": [
        {
          "role": "user",
          "content": message,
        }
      ]
    });
    request.headers.addAll(headers);

    http.StreamedResponse response = await request.send();

    if (response.statusCode == 200) {
      String responseString = await response.stream.bytesToString();
      Map<String, dynamic> jsonResponse = json.decode(responseString);
      String result = jsonResponse['choices'] != null? jsonResponse['choices'][0]['message']['content']: "No result found";
      print(responseString);
      return result;
    }
    else {
      print(response.reasonPhrase);
      return "ERROR";
    }
  }
  /// This has to happen only once per app
  void _initSpeech() async {
    print("음성인식 기능을 시작합니다.");
    _speechEnabled = await _speechToText.initialize();
    // setState(() {});
  }

  /// Each time to start a speech recognition session
  void _startListening() async {
    print("음성인식을 시작합니다.");
    await _speechToText.listen(onResult: _onSpeechResult);
    // setState(() {});
  }

  /// Manually stop the active speech recognition session
  /// Note that there are also timeouts that each platform enforces
  /// and the SpeechToText plugin supports setting timeouts on the
  /// listen method.
  void _stopListening() async {
    print("음성인식을 종료합니다.");
    await _speechToText.stop();
    // setState(() {});
  }

  /// This is the callback that the SpeechToText plugin calls when
  /// the platform returns recognized words.
  void _onSpeechResult(SpeechRecognitionResult result) {
    _lastWords = "";
    if(result.finalResult){
      _lastWords = result.recognizedWords;
      print("최종 인식된 문장: $_lastWords");
      setState(() {
        messages.insert(0, ChatMessage(
          text: _lastWords,
          user: user1, 
          createdAt: DateTime.now(),
        ));
      });

      Future<String> data = sendMessageToServer(_lastWords);
      data.then((value){
        setState(() {
          messages.insert(0, ChatMessage(
            text: value,
            user: user2, 
            createdAt: DateTime.now(),
            ));
        });
      });
    }    
  }
}