Firebase Realtime With Auth

/*
Firebase Security Rules
{
  "rules": {
    ".read": "auth != null",
  }
}
*/


import 'dart:async';

import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';

import 'googleSettings.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new HelloWorld(),
    );
  }
}

class HelloWorld extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          title: new Text('Login'),
        ),
        body: new Column(children: [
          new RaisedButton(
            child: new Text('Login'),
            onPressed: () {
              _login();
            },
          ),
          new RaisedButton(
            child: new Text('Go to data page'),
            onPressed: () {
              Navigator.push(
                context,
                new MaterialPageRoute(builder: (context) => new PopsiclesScreen()),
              );
            },
          )
        ]));
  }

  void _login() async {
    final FirebaseAuth _auth = FirebaseAuth.instance;
    final GoogleSignIn _googleSignIn = new GoogleSignIn();

    //do auth
    var googleAccount = await _googleSignIn.signIn();
    var googleAuth = await googleAccount.authentication;
    await _auth.signInWithGoogle(
      accessToken: googleAuth.accessToken,
      idToken: googleAuth.idToken,
    );
  }
}

class PopsiclesScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Container(
        child: new FutureBuilder<List<String>>(
      future: _getPopsicles(), // a Future<String> or null
      builder: (BuildContext context, AsyncSnapshot<List<String>> snapshot) {
        switch (snapshot.connectionState) {
          case ConnectionState.none:
            return new Text('Press button to start');
          case ConnectionState.waiting:
            return new Text('Awaiting result...');
          case ConnectionState.done:
            var widgets = snapshot.data.map((f) => new Text(f));
            return new ListView(
              children: widgets.toList(),
            );
          default:
            if (snapshot.hasError)
              return new Text('Error: ${snapshot.error}');
            else
              return new Text('Result: ${snapshot.data}');
        }
      },
    ));
  }

  Future<List<String>> _getPopsicles() async {
    //setup db
    var firebaseApp = await FirebaseApp.configure(
      name: 'db2',
      options: const FirebaseOptions(
        googleAppID: GoogleSettings.googleAppID,
        apiKey: GoogleSettings.apiKey,
        databaseURL: GoogleSettings.databaseURL,
      ),
    );
    var db = new FirebaseDatabase(app: firebaseApp);

    //get data
    var popsicles = new List<String>();
    var popsicleRef = db.reference().child('popcicles');
    var result = await popsicleRef.once();

    for (var item in result.value) {
      if (item != null) {
        popsicles.add(item.toString());
      }
    }

    return popsicles;
  }
}