VoiceToText

The VoiceToText class is a Dart class that provides functionality for speech recognition using the speech_to_text library. It allows to initialize speech recognition, start listening, stop listening and provide speech recognition results. Here is the detailed documentation of the class:

Constructors

VoiceToText({int? stopFor}) Constructor of the Speech class. It can accept an optional stopFor parameter representing the duration in seconds before stopping the recognition from the last spoken word. default value is 5 seconds.

Methods

initSpeech() -> void.

Initializes speech recognition.

startListening() -> void

Starts listening to the user's speech.

stop() -> void

Stops the active listener.

addListener(VoidCallback listener) -> void

Adds a listener to the listener list to be notified when the listener state changes.

notifyListeners() -> void

Notifies all registered listeners when the listener state changes.

get speechEnabled -> bool

Returns a boolean value indicating whether speech recognition is enabled on the device.

get isListening -> bool

Returns a boolean value indicating whether speech recognition is currently in progress.

get isNotListening -> bool

Returns a boolean value indicating whether speech recognition is not in process, i.e. is stopped.

get speechResult -> String

Returns the text recognized during active listening.

Example

import 'package:flutter/material.dart';
import 'package:voice_to_text/voice_to_text.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

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

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

  @override
  State<SpeechDemo> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<SpeechDemo> {
  final VoiceToText _speech = VoiceToText();
  String text = ""; //this is optional, I could get the text directly using speechResult
  @override
  void initState() {
    super.initState();
    _speech.initSpeech();
    _speech.addListener(() {
      setState(() {
        text = _speech.speechResult;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Speech Demo'),
      ),
      body: Container(
        padding: const EdgeInsets.all(10),
        alignment: Alignment.center,
        child: Column(
          textBaseline: TextBaseline.alphabetic,
          children: <Widget>[
            Text(
                _speech.isListening
                    ? "Listening...."
                    : 'Tap the microphone to start',
                style:
                    const TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
            Text(_speech.isNotListening
                ? text.isNotEmpty
                    ? text
                    : "Try speaking again"
                : ""),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed:
            // If not yet listening for speech start, otherwise stop
            _speech.isNotListening ? _speech.startListening : _speech.stop,
        tooltip: 'Listen',
        child: Icon(_speech.isNotListening ? Icons.mic_off : Icons.mic),
      ),
    );
  }
}

Permissions

Applications using this plugin require user permissions.

iOS

Add the following keys to your Info.plist file, located in <project root>/ios/Runner/Info.plist:

• NSSpeechRecognitionUsageDescription - describe why your app uses speech recognition. This is called Privacy - Speech Recognition Usage Description in the visual editor.
• NSMicrophoneUsageDescription - describe why your app needs access to the microphone. This is called Privacy - Microphone Usage Description in the visual editor.

Android

Add the record audio permission to your AndroidManifest.xml file, located in <project root>/android/app/src/main/AndroidManifest.xml.

• android.permission.RECORD_AUDIO - this permission is required for microphone access.
• android.permission.INTERNET - this permission is required because speech recognition may use remote services.
• android.permission.BLUETOOTH - this permission is required because speech recognition can use bluetooth headsets when connected.
• android.permission.BLUETOOTH_ADMIN - this permission is required because speech recognition can use bluetooth headsets when connected.
• android.permission.BLUETOOTH_CONNECT - this permission is required because speech recognition can use bluetooth headsets when connected.

    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>

Android SDK Version Error When Compiling

The speech_to_text plugin requires Android SDK version 21 or higher due to the utilization of speech functions introduced in that version of Android. To resolve this error, update the build.gradle file as follows:

android {
    ...
    defaultConfig {
        ...
        minSdkVersion 21
        targetSdkVersion 28
        ...
    }
}

Ensure that the minSdkVersion in your build.gradle is set to 21 or a higher version to successfully compile the project.

Documentation of speech_to_text

This package has been developed using the speech_to_text library as a base. If you are interested in learning more about this library, visit to speech_to_text.