How execute a Java function from a Constructor of React component throuhg webview

Question

I am making a video chat app which has to work in a webview of my android application.

So What I want is to set audio and video to true or false depending on java. it means if I clicked to audio call button in ui button I should set video to false and vice versa.

this.getUserMedia = navigator.mediaDevices.getUserMedia({
      audio: true,
      video: true
    })

Here is the full code for the Component containing the above lines.

import React, { Component } from 'react';
import MediaContainer from './MediaContainer'
import CommunicationContainer from './CommunicationContainer'
import { connect } from 'react-redux'
import store from '../store'
import io from 'socket.io-client'

class RoomPage extends Component {
  constructor(props) {
    super(props);
    this.getUserMedia = navigator.mediaDevices.getUserMedia({
      audio: true,
      video: true
    }).catch(e => alert('getUserMedia() error: ' + e.name))
    this.socket = io.connect();
  }
  componentDidMount() {
    this.props.addRoom();
  }
  render(){
    return (
      <div>
        <MediaContainer media={media => this.media = media} socket={this.socket} getUserMedia={this.getUserMedia} />
        <CommunicationContainer socket={this.socket} media={this.media} getUserMedia={this.getUserMedia} />
      </div>
    );
  }
}
const mapStateToProps = store => ({rooms: new Set([...store.rooms])});
const mapDispatchToProps = (dispatch, ownProps) => (
    {
      addRoom: () => store.dispatch({ type: 'ADD_ROOM', room: ownProps.match.params.room })
    }
  );
export default connect(mapStateToProps, mapDispatchToProps)(RoomPage);

If you can provide me with a sample code please. I am new in React, so please be as explicit as possible.