React Native Voice

A speech-to-text library for React Native.

npm i react-native-voice --save

• React Native Voice
  • Linking
    • Manually Link Android
    • Manually Link iOS
  • Usage
    • Example
  • API
  • Speech recognition options
  • Events
    • Handling errors
    • Android
    • iOS

Linking

Manually or automatically link the NativeModule

react-native link react-native-voice

Manually Link Android

• In android/setting.gradle

...
include ':react-native-voice', ':app'
project(':react-native-voice').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-voice/android')

• In android/app/build.gradle

...
dependencies {
    ...
    compile project(':react-native-voice')
}

• In MainApplication.java

import android.app.Application;
import com.facebook.react.ReactApplication;
import com.facebook.react.ReactPackage;
...
import com.wenkesj.voice.VoicePackage; // <------ Add this!
...

public class MainActivity extends Activity implements ReactApplication {
...
    @Override
    protected List<ReactPackage> getPackages() {
      return Arrays.<ReactPackage>asList(
        new MainReactPackage(),
        new VoicePackage() // <------ Add this!
        );
    }
}

Manually Link iOS

• Drag the Voice.xcodeproj from the react-native-voice/ios folder to the Libraries group on Xcode in your poject. Manual linking

• Click on your main project file (the one that represents the .xcodeproj) select Build Phases and drag the static library, lib.Voice.a, from the Libraries/Voice.xcodeproj/Products folder to Link Binary With Libraries

Usage

(Outdated) Full example for Android and iOS.

Example

import React, { Component } from "react";
import { TouchableOpacity, View, Text } from "react-native";
import Voice from "react-native-voice";

class VoiceTest extends Component {
  constructor(props) {
    Voice.onSpeechStart = this.onSpeechStartHandler.bind(this);
    Voice.onSpeechEnd = this.onSpeechEndHandler.bind(this);
    Voice.onSpeechPartialResults = this.onSpeechPartialResultsHandler.bind(this);
    Voice.onSpeechResults = this.onSpeechResultsHandler.bind(this);
    Voice.onSpeechError = this.onSpeechErrorHandler.bind(this);
  }

  componentWillUnmount() {
    // Remove all listeners
    Voice.removeAllListeners();
  }

  onSpeechStartHandler() {
    console.log("Speech started");
    // Update state to notify user that speech recognition has started
  }

   onSpeechPartialResultsHandler(e) {
    // e = { value: string[] }
    // Loop through e.value for speech transcription results
    console.log("Partial results", e);
  }

  onSpeechResultsHandler(e) {
    // e = { value: string[] }
    // Loop through e.value for speech transcription results
    console.log("Speech results", e);
  }

  onSpeechEndHandler(e) {
    // e = { error?: boolean }
    console.log("Speech ended", e);
  }

  onSpeechErrorHandler(e) {
    // e = { code?: string, message?: string }
    switch (e.code) { ... }
  }

  onStartButtonPress = async () => {
    try {
      await Voice.start("en_US");
    } catch (exception) {
      // exception = Error | { code: string, message?: string }
      onSpeechErrorHandler(exception);
    }
  };

  render() {
    return (
      <TouchableOpacity onPress={this.onStartButtonPress}>
        <View>
          <Text>Start</Text>
        </View>
      </TouchableOpacity>
    );
  }
}

API

Static access to the Voice API.

All methods now return a new Promise for async/await compatibility.

Method Name	Description	Platform
Voice.isAvailable()	Checks whether a speech recognition service is available on the system.	Android, iOS
Voice.isReady()	Checks whether speech recognition is ready to be used.	iOS
Voice.start(locale: string, options: {})	Starts speech recognition. See Speech recognition options for options.	Android, iOS
Voice.stop()	Stops listening for speech. Returns null if no error occurs.	Android, iOS
Voice.cancel()	Cancels the speech recognition. Returns null if no error occurs.	Android, iOS
Voice.destroy()	Destroys the current SpeechRecognizer instance. Returns null if no error occurs.	Android, iOS
Voice.removeAllListeners()	Cleans/nullifies overridden Voice static methods.	Android, iOS
Voice.isRecognizing()	Return if the SpeechRecognizer is recognizing.	Android, iOS
Voice.setCategory(category: string)	Sets the iOS audio category.	iOS
Voice.setPermissionRationaleAndroid(title: string, message: string)	Sets the permission rationale when requesting microphone permissions	Android
Voice.requestPermissionsAndroid()	Requests permissions to use the microphone. Note: already checked in Voice.start()	Android

Speech recognition options

Usage: Voice.start(locale: string, options: {})

Option Key	Description	Default	Platform
EXTRA_LANGUAGE_MODEL: string	Informs the recognizer which speech model to prefer when performing. See link for additional options	'LANGUAGE_MODEL_FREE_FORM'	Android
EXTRA_MAX_RESULTS: number	Optional limit on the maximum number of results to return. If omitted the recognizer will choose how many results to return	5	Android
EXTRA_PARTIAL_RESULTS: boolean	Optional boolean to indicate whether partial results should be returned by the recognizer as the user speaks	true	Android
EXTRA_SPEECH_INPUT_COMPLETE_ SILENCE_LENGTH_MILLIS: number	The amount of time that it should take after we stop hearing speech to consider the input complete.	not set	Android
EXTRA_SPEECH_INPUT_MINIMUM_ LENGTH_MILLIS: number	The minimum length of an utterance	not set	Android
continous: boolean	Enables continuous speech recognition	false	iOS

Events

Callbacks that are invoked when a native event emitted.

Event Name	Description	Event	Platform
Voice.onSpeechStart()	Invoked when .start() is called without error.	null	Android, iOS
Voice.onSpeechRecognized(event)	Invoked when speech is recognized.	{ isFinal: boolean }	Android, iOS
Voice.onSpeechEnd(event)	Invoked when SpeechRecognizer stops recognition.	{ error?: boolean }	Android, iOS
Voice.onSpeechError(event)	Invoked when an error occurs.	{ code: string, message?: string }	Android, iOS
Voice.onSpeechResults(event)	Invoked when SpeechRecognizer is finished recognizing.	{ value: Array<string> }	Android, iOS
Voice.onSpeechPartialResults(event)	Invoked when any results are computed.	{ value: Array<string> }	Android, iOS
Voice.onSpeechVolumeChanged(event)	Invoked when pitch that is recognized changed.	{ value: pitch in dB }	Android

Handling errors

This applies to Voice.onSpeechError(e) and when await Voice.start() throws an exception.

  onSpeechErrorHandler(e) {
    // e: { code: string, message?: string }
    // switch (e.code) { ... }
  }

  ...
  try {
    await Voice.start();
  } catch (e) {
    // Note: on Android this will *likely* return an Error object.
    // e: Error | { code: string, message?: string }
    // switch (e.code) { ... }
  }

Code	Description	Platform
permissions	User denied microphone/speech recognition permissions	Android, iOS
recognizer_busy	Speech recognition has already started	Android, iOS
not_available	Speech recognition is not available on the device	Android, iOS
audio	Audio engine / Audio session error	Android, iOS
network	Network error	Android
network_timeout	Network timeout error	Android
speech_timeout	Speech recognition timeout	Android
no_match	No recognition matches	Android
server	Server error	Android
restricted	Speech recognition is restricted	iOS
not_authorized	Speech recognition is not authorized	iOS
not_ready	Speech recognition is not ready to start	iOS
recognition_init	Speech recognition initialization failed	iOS
start_recording	[inputNode installTapOnBus:0...] call failed	iOS
input	Audio engine has no input node	iOS
recognition_fail	General failure while using recognition. Has a "message" prop	iOS

Permissions

Arguably the most important part.

Android

While the included VoiceTest app works without explicit permissions checks and requests, it may be necessary to add a permission request for RECORD_AUDIO for some configurations. Since Android M (6.0), user need to grant permission at runtime (and not during app installation). By default, calling the startSpeech method will invoke RECORD AUDIO permission popup to the user. This can be disabled by passing REQUEST_PERMISSIONS_AUTO: true in the options argument.

iOS

Need to include permissions for NSMicrophoneUsageDescription and NSSpeechRecognitionUsageDescription inside Info.plist for iOS. See the included VoiceTest for how to handle these cases.

<dict>
  ...
  <key>NSMicrophoneUsageDescription</key>
  <string>Description of why you require the use of the microphone</string>
  <key>NSSpeechRecognitionUsageDescription</key>
  <string>Description of why you require the use of the speech recognition</string>
  ...
</dict>

Please see the documentation provided by ReactNative for this: PermissionsAndroid

Contibutors

• @asafron
• @BrendanFDMoore
• @brudny
• @chitezh
• @ifsnow
• @jamsch
• @misino
• @Noitidart
• @ohtangza & @hayanmind
• @rudiedev6
• @tdonia
• @wenkesj