Text to Speech Conversion with Natural Voices in React Native

React Native Text to Speech Conversion

This is an example to show how to do Text to Speech Conversion with Natural Voices in React Native – Text Reader. As the name suggests we are going to see how can you implement a text reader feature in your React Native App. We are going to use the TTS engine to convert our Text into Speech. This is a very popular feature nowadays. If you have observed each and every newspaper or content provider application are implementing Text to Speech conversion feature and getting the attention of their customer too.

For text to speech conversion, we are using a very easy to integrate react-native-tts library which provides a Tts component. Tts component provides the support of different voices and has listeners for each state as the reader started, finished, canceled.

To get Different Voices

const voices = await Tts.voices();
const availableVoices = voices
	.filter(v => !v.networkConnectionRequired && !v.notInstalled)
	.map(v => {
	return { id: v.id, name: v.name, language: v.language };
});

Add different Listeners

Tts.addEventListener('tts-start', event =>
  this.setState({ ttsStatus: 'started' })
);
Tts.addEventListener('tts-finish', event =>
  this.setState({ ttsStatus: 'finished' })
);
Tts.addEventListener('tts-cancel', event =>
  this.setState({ ttsStatus: 'cancelled' })
);

In this example, we are going to make a screen with 2 sliders to control the speed and pitch of the voice. We will have a TextInput to get the text to read and a button to start reading. We will also have a list of different voices and languages below which will help us to try different combinations.

Now let’s get started with the example and see how to convert text to speech.

To Make a React Native App

Getting started with React Native will help you to know more about the way you can make a React Native project. We are going to use react-native init to make our React Native App. Assuming that you have node installed, you can use npm to install the react-native-cli command line utility. Open the terminal and go to the workspace and run

npm install -g react-native-cli

Run the following commands to create a new React Native project

react-native init ProjectName

If you want to start a new project with a specific React Native version, you can use the --version argument:

react-native init ProjectName --version X.XX.X

react-native init ProjectName --version react-native@next

This will make a project structure with an index file named App.js in your project directory.

Installation of Dependency

To use Tts component we have to install react-native-tts dependency. To install the dependency open the terminal and jump into your project

cd ProjectName

Now install the dependency

npm install react-native-tts --save

For this example, we are using Slider component provided by react-native-community to control the pitch and speed of voice so we will also have to install the following dependency for the same

npm install @react-native-community/slider --save

CocoaPods Installation

After the updation of React Native 0.60, they have introduced autolinking so we do not require to link the libraries but need to install pods. In this example, we need to install the pods for react-native-tts and Slider.

Please use the following command to install CocoaPods

cd ios && pod install && cd ..

Code to Convert Text to Speech

Now Open App.js in any code editor and replace the code with the following code.

App.js

//Example of Text to Speech conversion
import React, { Component } from 'react';
//Import React
import {
  Platform,
  StyleSheet,
  Text,
  View,
  Button,
  FlatList,
  TextInput,
  Keyboard,
  TouchableOpacity,
} from 'react-native';
//Import basic component from React Native
import Slider from '@react-native-community/slider';
//Import slider for the tuning of pitch and speed
import Tts from 'react-native-tts';
//Import library for Text to Speech

export default class App extends Component {
  state = {
    voices: [],
    ttsStatus: 'initiliazing',
    selectedVoice: null,
    speechRate: 0.5,
    speechPitch: 1,
    text: 'Enter Text like Hello About React',
  };

  constructor(props) {
    super(props);
    Tts.addEventListener('tts-start', event =>
      this.setState({ ttsStatus: 'started' })
    );
    Tts.addEventListener('tts-finish', event =>
      this.setState({ ttsStatus: 'finished' })
    );
    Tts.addEventListener('tts-cancel', event =>
      this.setState({ ttsStatus: 'cancelled' })
    );
    Tts.setDefaultRate(this.state.speechRate);
    Tts.setDefaultPitch(this.state.speechPitch);
    Tts.getInitStatus().then(this.initTts);
  }

  initTts = async () => {
    const voices = await Tts.voices();
    const availableVoices = voices
      .filter(v => !v.networkConnectionRequired && !v.notInstalled)
      .map(v => {
        return { id: v.id, name: v.name, language: v.language };
      });
    let selectedVoice = null;
    if (voices && voices.length > 0) {
      selectedVoice = voices[0].id;
      try {
        await Tts.setDefaultLanguage(voices[0].language);
      } catch (err) {
        //Samsung S9 has always this error: "Language is not supported"
        console.log(`setDefaultLanguage error `, err);
      }
      await Tts.setDefaultVoice(voices[0].id);
      this.setState({
        voices: availableVoices,
        selectedVoice,
        ttsStatus: 'initialized',
      });
    } else {
      this.setState({ ttsStatus: 'initialized' });
    }
  };

  readText = async () => {
    Tts.stop();
    Tts.speak(this.state.text);
  };

  setSpeechRate = async rate => {
    await Tts.setDefaultRate(rate);
    this.setState({ speechRate: rate });
  };

  setSpeechPitch = async rate => {
    await Tts.setDefaultPitch(rate);
    this.setState({ speechPitch: rate });
  };

  onVoicePress = async voice => {
    try {
      await Tts.setDefaultLanguage(voice.language);
    } catch (err) {
      // My Samsung S9 has always this error: "Language is not supported"
      console.log(`setDefaultLanguage error `, err);
    }
    await Tts.setDefaultVoice(voice.id);
    this.setState({ selectedVoice: voice.id });
  };

  renderVoiceItem = ({ item }) => {
    return (
      <Button
        title={`${item.language} - ${item.name || item.id}`}
        color={this.state.selectedVoice === item.id ? undefined : '#969696'}
        onPress={() => this.onVoicePress(item)}
      />
    );
  };

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.title}>
          Example of Text to Speech Conversion in React Native
        </Text>
        <View style={styles.sliderContainer}>
          <Text style={styles.sliderLabel}>
            {`Speed: ${this.state.speechRate.toFixed(2)}`}
          </Text>
          <Slider
            style={styles.slider}
            minimumValue={0.01}
            maximumValue={0.99}
            value={this.state.speechRate}
            onSlidingComplete={this.setSpeechRate}
          />
        </View>
        <View style={styles.sliderContainer}>
          <Text style={styles.sliderLabel}>
            {`Pitch: ${this.state.speechPitch.toFixed(2)}`}
          </Text>
          <Slider
            style={styles.slider}
            minimumValue={0.5}
            maximumValue={2}
            value={this.state.speechPitch}
            onSlidingComplete={this.setSpeechPitch}
          />
        </View>
        <Text style={styles.sliderContainer}>
          {`Selected Voice: ${this.state.selectedVoice || ''}`}
        </Text>
        <TextInput
          style={styles.textInput}
          onChangeText={text => this.setState({ text })}
          value={this.state.text}
          onSubmitEditing={Keyboard.dismiss}
        />
        <TouchableOpacity style={styles.button} onPress={this.readText}>
          <Text>
            Click to Read Text ({`Status: ${this.state.ttsStatus || ''}`})
          </Text>
        </TouchableOpacity>
        <Text style={styles.sliderLabel}>Select the Voice from below</Text>
        <FlatList
          style={{ width: '100%', marginTop: 5 }}
          keyExtractor={item => item.id}
          renderItem={this.renderVoiceItem}
          extraData={this.state.selectedVoice}
          data={this.state.voices}
        />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    padding: 16,
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  },
  button: {
    alignItems: 'center',
    backgroundColor: '#DDDDDD',
    padding: 10,
    width: 300,
    margin: 10,
  },
  title: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  sliderContainer: {
    flexDirection: 'row',
    justifyContent: 'center',
    alignItems: 'center',
    width: 300,
    padding: 5,
  },
  sliderLabel: {
    textAlign: 'center',
    marginRight: 20,
  },
  slider: {
    flex: 1,
  },
  textInput: {
    borderColor: 'gray',
    borderWidth: 1,
    color: 'black',
    width: 300,
    textAlign: 'center',
    height: 40,
  },
});

To Run the React Native App

Open the terminal again and jump into your project using.

cd ProjectName

To run the project on an Android Virtual Device or on real debugging device

react-native run-android

or on the iOS Simulator by running

react-native run-ios (macOS only).

Output Screenshots

This was text to speech conversion with natural voices in React Native. If you have any doubts or you want to share something about the topic you can comment below or contact us here. There will be more posts coming soon. Stay tuned!

Hope you liked it. 🙂