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) => setTtsStatus('started')
);
Tts.addEventListener(
  'tts-finish',
  (_event) => setTtsStatus('finished')
);
Tts.addEventListener(
  'tts-cancel',
  (_event) => setTtsStatus('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 command line interface to make our React Native App.

If you have previously installed a global react-native-cli package, please remove it as it may cause unexpected issues:

npm uninstall -g react-native-cli @react-native-community/cli

Run the following commands to create a new React Native project

npx react-native init ProjectName

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

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

Note If the above command is failing, you may have old version of react-native or react-native-cli installed globally on your pc. Try uninstalling the cli and run the cli using npx.

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

Please use the following command to install CocoaPods

npx pod-install

Code to Convert Text to Speech

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

App.js

// Text to Speech Conversion with Natural Voices in React Native
// https://aboutreact.com/react-native-text-to-speech/

// import React in our code
import React, {useState, useEffect} from 'react';

// import all the components we are going to use
import {
  SafeAreaView,
  StyleSheet,
  Text,
  View,
  FlatList,
  TextInput,
  Keyboard,
  TouchableOpacity,
} from 'react-native';

// import slider for the tuning of pitch and speed
import Slider from '@react-native-community/slider';

// import Tts Text to Speech
import Tts from 'react-native-tts';

const App = () => {
  const [voices, setVoices] = useState([]);
  const [ttsStatus, setTtsStatus] = useState('initiliazing');
  const [selectedVoice, setSelectedVoice] = useState(null);
  const [speechRate, setSpeechRate] = useState(0.5);
  const [speechPitch, setSpeechPitch] = useState(1);
  const [
    text,
    setText
  ] = useState('Enter Text like Hello About React');

  useEffect(() => {
    Tts.addEventListener(
      'tts-start',
      (_event) => setTtsStatus('started')
    );
    Tts.addEventListener(
      'tts-finish',
      (_event) => setTtsStatus('finished')
    );
    Tts.addEventListener(
      'tts-cancel',
      (_event) => setTtsStatus('cancelled')
    );
    Tts.setDefaultRate(speechRate);
    Tts.setDefaultPitch(speechPitch);
    Tts.getInitStatus().then(initTts);
    return () => {
      Tts.removeEventListener(
        'tts-start',
        (_event) => setTtsStatus('started')
      );
      Tts.removeEventListener(
        'tts-finish',
        (_event) => setTtsStatus('finished'),
      );
      Tts.removeEventListener(
        'tts-cancel',
        (_event) => setTtsStatus('cancelled'),
      );
    };
  }, []);

  const 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);
      setVoices(availableVoices);
      setSelectedVoice(selectedVoice);
      setTtsStatus('initialized');
    } else {
      setTtsStatus('initialized');
    }
  };

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

  const updateSpeechRate = async (rate) => {
    await Tts.setDefaultRate(rate);
    setSpeechRate(rate);
  };

  const updateSpeechPitch = async (rate) => {
    await Tts.setDefaultPitch(rate);
    setSpeechPitch(rate);
  };

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

  const renderVoiceItem = ({item}) => {
    return (
      <TouchableOpacity
        style={{
          backgroundColor: selectedVoice === item.id ? 
          '#DDA0DD' : '#5F9EA0',
        }}
        onPress={() => onVoicePress(item)}>
        <Text style={styles.buttonTextStyle}>
          {`${item.language} - ${item.name || item.id}`}
        </Text>
      </TouchableOpacity>
    );
  };

  return (
    <SafeAreaView style={styles.container}>
      <View style={styles.container}>
        <Text style={styles.titleText}>
          Text to Speech Conversion with Natural Voices
        </Text>
        <View style={styles.sliderContainer}>
          <Text style={styles.sliderLabel}>
            {`Speed: ${speechRate.toFixed(2)}`}
          </Text>
          <Slider
            style={styles.slider}
            minimumValue={0.01}
            maximumValue={0.99}
            value={speechRate}
            onSlidingComplete={updateSpeechRate}
          />
        </View>
        <View style={styles.sliderContainer}>
          <Text style={styles.sliderLabel}>
            {`Pitch: ${speechPitch.toFixed(2)}`}
          </Text>
          <Slider
            style={styles.slider}
            minimumValue={0.5}
            maximumValue={2}
            value={speechPitch}
            onSlidingComplete={updateSpeechPitch}
          />
        </View>
        <Text style={styles.sliderContainer}>
          {`Selected Voice: ${selectedVoice || ''}`}
        </Text>
        <TextInput
          style={styles.textInput}
          onChangeText={(text) => setText(text)}
          value={text}
          onSubmitEditing={Keyboard.dismiss}
        />
        <TouchableOpacity
          style={styles.buttonStyle}
          onPress={readText}>
          <Text style={styles.buttonTextStyle}>
            Click to Read Text ({`Status: ${ttsStatus || ''}`})
          </Text>
        </TouchableOpacity>
        <Text style={styles.sliderLabel}>
          Select the Voice from below
        </Text>
        <FlatList
          style={{width: '100%', marginTop: 5}}
          keyExtractor={(item) => item.id}
          renderItem={renderVoiceItem}
          extraData={selectedVoice}
          data={voices}
        />
      </View>
    </SafeAreaView>
  );
};

export default App;

const styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: 'column',
    padding: 5,
  },
  titleText: {
    fontSize: 22,
    textAlign: 'center',
    fontWeight: 'bold',
  },
  buttonStyle: {
    justifyContent: 'center',
    marginTop: 15,
    padding: 10,
    backgroundColor: '#8ad24e',
  },
  buttonTextStyle: {
    color: '#fff',
    textAlign: 'center',
  },
  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: '100%',
    textAlign: 'center',
    height: 40,
  },
});

To Run the React Native App

Open the terminal again and jump into your project using.

cd ProjectName

1. Start Metro Bundler

First, you will need to start Metro, the JavaScript bundler that ships with React Native. To start Metro bundler run following command

npx react-native start

Once you start Metro Bundler it will run forever on your terminal until you close it. Let Metro Bundler run in its own terminal. Open a new terminal and run the application.

2. Start React Native Application

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

npx react-native run-android

or on the iOS Simulator by running (macOS only)

npx react-native run-ios

Error Possibility

If you face any issues while running the Android app, you can make the following changes

In project/build.gradle

1. Update minSdkVersion to 23
2. Add kotlin_version in buildscript >> ext and a dependency in buildscript >> dependencies

buildscript {
    ext {
        ...
        minSdkVersion = 21
        ...
        kotlin_version = '1.5.10'

    }
    repositories {
       ...
    }
    dependencies {
        ...
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
       ...
    }
}

3. Add following in project/app/build.gradle

apply plugin: "kotlin-android"
apply plugin: "kotlin-android-extensions"

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. 🙂