App.js

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 * @flow
 */

import React, { Component } from 'react';
import {
    AppRegistry,
    StyleSheet,
    Text,
    View,
    TouchableOpacity,
    ActivityIndicator
} from 'react-native';
import { LoginButton, AccessToken, LoginManager } from 'react-native-fbsdk';
import firebase from 'firebase';
const config = {
    apiKey: "AIzaSyAfpxJrikhNNKy0p2s5a2XdGHh1PrNaKJ0",
    authDomain: "fir-login-6af59.firebaseapp.com",
    databaseURL: "https://fir-login-6af59.firebaseio.com",
    storageBucket: "fir-login-6af59.appspot.com",
    messagingSenderId: "86655694512"
};
firebase.initializeApp(config);

export default class facebook_login extends Component {
    state = {
        logged: false,
        animating: false
    }

    handleLogin = () => {
        if (!this.state.logged) {
            LoginManager.logInWithPublishPermissions(['publish_actions'])
                .then((result) => {
                    if (result.isCancelled) {
                        alert('Cancel login');
                    }
                    // } else if (result.declinedPermissions) {
                    //     alert('declinedPermissions');
                    // } else {
                    this.setState({ logged: true });
                    AccessToken.getCurrentAccessToken().then(
                        (data) => {
                            alert(data.accessToken.toString())
                        }
                    ).catch(error => alert(error));
                })
                .catch(error => console.log(error));
        } else {
            this.setState({ logged: false });
            LoginManager.logOut();
        }
    }

    onLogin = async () => {
        try {
            this.setState({
                animating: true
            });
            const result = await LoginManager.logInWithReadPermissions(['public_profile', 'email']);
            const tokenData = await AccessToken.getCurrentAccessToken();
            const token = tokenData.accessToken.toString();
            const credential = firebase.auth.FacebookAuthProvider.credential(token);
            const user = await firebase.auth().signInWithCredential(credential);
            firebase.database().ref(`/users/${user.uid}/profile`).set({
                name: user.displayName,
                email: user.email,
                avatar: user.photoURL
            });
            this.setState({
                animating: false
            });
        } catch (error) {
            this.setState({
                animating: false
            });
            console.log(error.message);
            // do something here
        }
    }
    render() {
        return (
            <View style={styles.container}>
                <Text style={styles.welcome}>
                    Welcome to React Native!
        </Text>
                <Text style={styles.instructions}>
                    To get started, edit index.android.js
        </Text>
                <ActivityIndicator
                    animating={this.state.animating}
                    color="#ddd"
                    size="large"
                />
                <LoginButton
                    publishPermissions={["publish_actions"]}
                    onLoginFinished={
                        (error, result) => {
                            if (error) {
                                alert("login has error: " + result.error);
                            } else if (result.isCancelled) {
                                alert("login is cancelled.");
                            } else {
                                AccessToken.getCurrentAccessToken().then(
                                    (data) => {
                                        alert(data.accessToken.toString())
                                    }
                                )
                            }
                        }
                    }
                    onLogoutFinished={() => alert("logout.")} />
                <TouchableOpacity
                    onPress={this.onLogin}
                    style={{
                        marginTop: 10,
                        padding: 10,
                        backgroundColor: 'green',
                        borderRadius: 5,
                    }}
                >
                    <Text style={{ color: '#fff' }}>
                        {this.state.logged ? 'Đăng xuất' : 'Đăng nhập'}
                    </Text>
                </TouchableOpacity>
            </View>
        );
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: '#F5FCFF',
    },
    welcome: {
        fontSize: 20,
        textAlign: 'center',
        margin: 10,
    },
    instructions: {
        textAlign: 'center',
        color: '#333333',
        marginBottom: 5,
    },
});

AppRegistry.registerComponent('facebook_login', () => facebook_login);