speech_to_text 5.1.0

A Flutter plugin that exposes device specific speech to text recognition capability.

example/lib/main.dart

import 'dart:async';
import 'dart:math';

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(SpeechSampleApp());

class SpeechSampleApp extends StatefulWidget {
  @override
  _SpeechSampleAppState createState() => _SpeechSampleAppState();
}

/// An example that demonstrates the basic functionality of the
/// SpeechToText plugin for using the speech recognition capability
/// of the underlying platform.
class _SpeechSampleAppState extends State<SpeechSampleApp> {
  bool _hasSpeech = false;
  bool _logEvents = false;
  double level = 0.0;
  double minSoundLevel = 50000;
  double maxSoundLevel = -50000;
  String lastWords = '';
  String lastError = '';
  String lastStatus = '';
  String _currentLocaleId = '';
  List<LocaleName> _localeNames = [];
  final SpeechToText speech = SpeechToText();

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

  /// This initializes SpeechToText. That only has to be done
  /// once per application, though calling it again is harmless
  /// it also does nothing. The UX of the sample app ensures that
  /// it can only be called once.
  Future<void> initSpeechState() async {
    _logEvent('Initialize');
    var hasSpeech = await speech.initialize(
        onError: errorListener,
        onStatus: statusListener,
        debugLogging: true,
        finalTimeout: Duration(milliseconds: 0));
    if (hasSpeech) {
      // Get the list of languages installed on the supporting platform so they
      // can be displayed in the UI for selection by the user.
      _localeNames = await speech.locales();

      var systemLocale = await speech.systemLocale();
      _currentLocaleId = systemLocale?.localeId ?? '';
    }

    if (!mounted) return;

    setState(() {
      _hasSpeech = hasSpeech;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Speech to Text Example'),
        ),
        body: Column(children: [
          HeaderWidget(),
          Container(
            child: Column(
              children: <Widget>[
                InitSpeechWidget(_hasSpeech, initSpeechState),
                SpeechControlWidget(_hasSpeech, speech.isListening,
                    startListening, stopListening, cancelListening),
                SessionOptionsWidget(_currentLocaleId, _switchLang,
                    _localeNames, _logEvents, _switchLogging),
              ],
            ),
          ),
          Expanded(
            flex: 4,
            child: RecognitionResultsWidget(lastWords: lastWords, level: level),
          ),
          Expanded(
            flex: 1,
            child: ErrorWidget(lastError: lastError),
          ),
          SpeechStatusWidget(speech: speech),
        ]),
      ),
    );
  }

  // This is called each time the users wants to start a new speech
  // recognition session
  void startListening() {
    _logEvent('start listening');
    lastWords = '';
    lastError = '';
    // Note that `listenFor` is the maximum, not the minimun, on some
    // recognition will be stopped before this value is reached.
    // Similarly `pauseFor` is a maximum not a minimum and may be ignored
    // on some devices.
    speech.listen(
        onResult: resultListener,
        listenFor: Duration(seconds: 30),
        pauseFor: Duration(seconds: 5),
        partialResults: true,
        localeId: _currentLocaleId,
        onSoundLevelChange: soundLevelListener,
        cancelOnError: true,
        listenMode: ListenMode.confirmation);
    setState(() {});
  }

  void stopListening() {
    _logEvent('stop');
    speech.stop();
    setState(() {
      level = 0.0;
    });
  }

  void cancelListening() {
    _logEvent('cancel');
    speech.cancel();
    setState(() {
      level = 0.0;
    });
  }

  /// This callback is invoked each time new recognition results are
  /// available after `listen` is called.
  void resultListener(SpeechRecognitionResult result) {
    _logEvent(
        'Result listener final: ${result.finalResult}, words: ${result.recognizedWords}');
    setState(() {
      lastWords = '${result.recognizedWords} - ${result.finalResult}';
    });
  }

  void soundLevelListener(double level) {
    minSoundLevel = min(minSoundLevel, level);
    maxSoundLevel = max(maxSoundLevel, level);
    // _logEvent('sound level $level: $minSoundLevel - $maxSoundLevel ');
    setState(() {
      this.level = level;
    });
  }

  void errorListener(SpeechRecognitionError error) {
    _logEvent(
        'Received error status: $error, listening: ${speech.isListening}');
    setState(() {
      lastError = '${error.errorMsg} - ${error.permanent}';
    });
  }

  void statusListener(String status) {
    _logEvent(
        'Received listener status: $status, listening: ${speech.isListening}');
    setState(() {
      lastStatus = '$status';
    });
  }

  void _switchLang(selectedVal) {
    setState(() {
      _currentLocaleId = selectedVal;
    });
    print(selectedVal);
  }

  void _logEvent(String eventDescription) {
    if (_logEvents) {
      var eventTime = DateTime.now().toIso8601String();
      print('$eventTime $eventDescription');
    }
  }

  void _switchLogging(bool? val) {
    setState(() {
      _logEvents = val ?? false;
    });
  }
}

/// Displays the most recently recognized words and the sound level.
class RecognitionResultsWidget extends StatelessWidget {
  const RecognitionResultsWidget({
    Key? key,
    required this.lastWords,
    required this.level,
  }) : super(key: key);

  final String lastWords;
  final double level;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        Center(
          child: Text(
            'Recognized Words',
            style: TextStyle(fontSize: 22.0),
          ),
        ),
        Expanded(
          child: Stack(
            children: <Widget>[
              Container(
                color: Theme.of(context).selectedRowColor,
                child: Center(
                  child: Text(
                    lastWords,
                    textAlign: TextAlign.center,
                  ),
                ),
              ),
              Positioned.fill(
                bottom: 10,
                child: Align(
                  alignment: Alignment.bottomCenter,
                  child: Container(
                    width: 40,
                    height: 40,
                    alignment: Alignment.center,
                    decoration: BoxDecoration(
                      boxShadow: [
                        BoxShadow(
                            blurRadius: .26,
                            spreadRadius: level * 1.5,
                            color: Colors.black.withOpacity(.05))
                      ],
                      color: Colors.white,
                      borderRadius: BorderRadius.all(Radius.circular(50)),
                    ),
                    child: IconButton(
                      icon: Icon(Icons.mic),
                      onPressed: () => null,
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Text(
        'Speech recognition available',
        style: TextStyle(fontSize: 22.0),
      ),
    );
  }
}

/// Display the current error status from the speech
/// recognizer
class ErrorWidget extends StatelessWidget {
  const ErrorWidget({
    Key? key,
    required this.lastError,
  }) : super(key: key);

  final String lastError;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        Center(
          child: Text(
            'Error Status',
            style: TextStyle(fontSize: 22.0),
          ),
        ),
        Center(
          child: Text(lastError),
        ),
      ],
    );
  }
}

/// Controls to start and stop speech recognition
class SpeechControlWidget extends StatelessWidget {
  const SpeechControlWidget(this.hasSpeech, this.isListening,
      this.startListening, this.stopListening, this.cancelListening,
      {Key? key})
      : super(key: key);

  final bool hasSpeech;
  final bool isListening;
  final void Function() startListening;
  final void Function() stopListening;
  final void Function() cancelListening;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceAround,
      children: <Widget>[
        TextButton(
          onPressed: !hasSpeech || isListening ? null : startListening,
          child: Text('Start'),
        ),
        TextButton(
          onPressed: isListening ? stopListening : null,
          child: Text('Stop'),
        ),
        TextButton(
          onPressed: isListening ? cancelListening : null,
          child: Text('Cancel'),
        )
      ],
    );
  }
}

class SessionOptionsWidget extends StatelessWidget {
  const SessionOptionsWidget(this.currentLocaleId, this.switchLang,
      this.localeNames, this.logEvents, this.switchLogging,
      {Key? key})
      : super(key: key);

  final String currentLocaleId;
  final void Function(String?) switchLang;
  final void Function(bool?) switchLogging;
  final List<LocaleName> localeNames;
  final bool logEvents;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceAround,
      children: <Widget>[
        Row(
          children: [
            Text('Language: '),
            DropdownButton<String>(
              onChanged: (selectedVal) => switchLang(selectedVal),
              value: currentLocaleId,
              items: localeNames
                  .map(
                    (localeName) => DropdownMenuItem(
                      value: localeName.localeId,
                      child: Text(localeName.name),
                    ),
                  )
                  .toList(),
            ),
          ],
        ),
        Row(
          children: [
            Text('Log events: '),
            Checkbox(
              value: logEvents,
              onChanged: switchLogging,
            ),
          ],
        )
      ],
    );
  }
}

class InitSpeechWidget extends StatelessWidget {
  const InitSpeechWidget(this.hasSpeech, this.initSpeechState, {Key? key})
      : super(key: key);

  final bool hasSpeech;
  final Future<void> Function() initSpeechState;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceAround,
      children: <Widget>[
        TextButton(
          onPressed: hasSpeech ? null : initSpeechState,
          child: Text('Initialize'),
        ),
      ],
    );
  }
}

/// Display the current status of the listener
class SpeechStatusWidget extends StatelessWidget {
  const SpeechStatusWidget({
    Key? key,
    required this.speech,
  }) : super(key: key);

  final SpeechToText speech;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: EdgeInsets.symmetric(vertical: 20),
      color: Theme.of(context).backgroundColor,
      child: Center(
        child: speech.isListening
            ? Text(
                "I'm listening...",
                style: TextStyle(fontWeight: FontWeight.bold),
              )
            : Text(
                'Not listening',
                style: TextStyle(fontWeight: FontWeight.bold),
              ),
      ),
    );
  }
}