Google Signin Flutter

import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  GoogleSignIn _googleSignIn = new GoogleSignIn(
    scopes: <String>[
      'profile',
      'email',
      'https://www.googleapis.com/auth/contacts.readonly',
    ],
  );

  Future<void> _handleSignIn() async {
    try {
      await _googleSignIn.signIn();
      print("signed in" + _googleSignIn.currentUser.email);
    } catch (error) {
      print(error);
    }
  }

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: RaisedButton(onPressed: () {
          _handleSignIn();
        }),
      ),
    );
  }
}





--------------------library--------------------

 google_sign_in: ^4.0.1+1

 firebase_auth: ^0.6.6