index.android.js

import React,{Component} from 'react';
import {
  View,
  Button
} from 'react-native';       
import ToastModule from 'react-native-android-toast';

export default class ToastDemo extends Component {
  showToast = () =>{
    ToastModule.show("Hello World");
  }
  render() {
    return (
        <View style={{flex: 1, justifyContent: 'center', alignItems: 'center'}}>
          <Button onPress={showToast} title= "Clike Me" />
        </View>
    );
  }
}