speech2text continuous listening

main.dart

import 'package:flutter/material.dart';
import 'package:speech_to_text/speech_recognition_error.dart';
import 'package:speech_to_text/speech_recognition_result.dart';
import 'package:speech_to_text/speech_to_text.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  MyHomePageState createState() => MyHomePageState();
}

class MyHomePageState extends State<MyHomePage> {
  final SpeechToText _speechToText = SpeechToText();
  bool _speechEnabled = false;
  bool _speechAvailable = false;
  String _lastWords = '';
  String _currentWords = '';

  // final String _selectedLocaleId = 'es_MX';

  printLocales() async {
    var locales = await _speechToText.locales();
    for (var local in locales) {
      debugPrint(local.name);
      debugPrint(local.localeId);
    }
  }

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

  void errorListener(SpeechRecognitionError error) async {
    debugPrint(error.errorMsg.toString());
    // if (_speechEnabled) {
    //   await _startListening();
    // }
  }

  void statusListener(String status) async {
    debugPrint("status $status");
    if (status == "done" && _speechEnabled) {
      if (_currentWords.isNotEmpty) {
        setState(() {
          _lastWords += " $_currentWords";
          _currentWords = "";
          _speechEnabled = false;
        });
      } else {
        // wait 50 mil seconds and try again
        await Future.delayed(Duration(milliseconds: 50));
      }
      await _startListening();
    }
  }

  /// This has to happen only once per app
  void _initSpeech() async {
    _speechAvailable = await _speechToText.initialize(
        onError: errorListener, onStatus: statusListener);
    setState(() {});
  }

  /// Each time to start a speech recognition session
  Future _startListening() async {
    debugPrint("=================================================");
    await _stopListening();
    await Future.delayed(const Duration(milliseconds: 50));
    await _speechToText.listen(
        onResult: _onSpeechResult,
        // localeId: _selectedLocaleId,
        cancelOnError: false,
        partialResults: true,
        listenFor: const Duration(seconds: 10)
        // listenMode: ListenMode.dictation
        );
    setState(() {
      _speechEnabled = true;
    });
  }

  /// 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.
  Future _stopListening() async {
    setState(() {
      _speechEnabled = false;
    });
    await _speechToText.stop();
  }

  /// This is the callback that the SpeechToText plugin calls when
  /// the platform returns recognized words.
  void _onSpeechResult(SpeechRecognitionResult result) {
    setState(() {
      _currentWords = result.recognizedWords;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Speech Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Container(
              padding: const EdgeInsets.all(16),
              child: const Text(
                'Recognized words:',
                style: TextStyle(fontSize: 20.0),
              ),
            ),
            Expanded(
              child: Container(
                padding: const EdgeInsets.all(16),
                child: Text(
                  _lastWords.isNotEmpty
                      ? '$_lastWords $_currentWords'
                      : _speechAvailable
                          ? 'Tap the microphone to start listening...'
                          : 'Speech not available',
                ),
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed:
            _speechToText.isNotListening ? _startListening : _stopListening,
        tooltip: 'Listen',
        child: Icon(_speechToText.isNotListening ? Icons.mic_off : Icons.mic),
      ),
    );
  }
}