Tried to show an alert while not attached to an Activity

• android 7.0
• react-native 0.43
• when i use the ‘alert’ in an android app which integrated the react-native the code after:

	import React, {Component} from 'react';
	import {
	    AppRegistry,
	    StyleSheet,
	    Text,
	    View,
	    Navigator,
	    Button,
	    Alert,
	} from 'react-native';
	
	
	class HelloWorld extends React.Component {
	    show(){
	        Alert.alert(
	            'Alert Title',
	            'alertMessage',
	        )
	    }
	    render() {
	        return (
	            < View
	                style={styles.container
	                }>
	                <Text
	                    style={styles.hello
	                    }>
	                    Hello, World </ Text >
	                <Button title="a"
	                        onPress={this.show.bind(this)
	                        }/>
	            </ View >
	        )
	    }
	}
	
	var styles = StyleSheet.create({
	    container: {
	        flex: 1,
	        justifyContent: 'center',
	    },
	    hello: {
	        fontSize: 20,
	        textAlign: 'center',
	        margin: 10,
	    },
	});
	
	AppRegistry.registerComponent('a', () => HelloWorld);

it give me the warning like this and no dialog show