index.js

import React from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View
} from 'react-native';
import Icon from 'react-native-vector-icons/FontAwesome';
const myButton = (
  <Icon.Button
    name="facebook"
    backgroundColor="#3b5998"
    onPress={this.loginWithFacebook}
  >
    Login with Facebook
  </Icon.Button>
);

const customTextButton = (
  <Icon.Button name="facebook" backgroundColor="#3b5998">
    <Text style={{ fontFamily: 'Arial', fontSize: 15 }}>
      Login with Facebook
    </Text>
  </Icon.Button>
);
class HelloWorld extends React.Component {
  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.hello}>Hello, World</Text>
        <Icon.Button
    name="facebook"
    backgroundColor="#3b5998"
    onPress={this.loginWithFacebook}
  >
    Login with Facebook
  </Icon.Button>
  <Icon.Button name="comments" backgroundColor="#3b5998">
    <Text style={{ fontFamily: 'Arial', fontSize: 15 }}>
      Login with Facebook
    </Text>
  </Icon.Button>
      </View>
    );
  }
}
var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center'
  },
  hello: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10
  }
});

AppRegistry.registerComponent(
  'MyReactNativeApp',
  () => HelloWorld
);