app

main.dart

import 'dart:async';
import 'dart:io';

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

Future<void> main() async {
  final FirebaseApp app = await FirebaseApp.configure(
    name: 'db2',
    options: Platform.isIOS
        ? const FirebaseOptions(
      googleAppID: 'todo',
      gcmSenderID: 'todo',
      databaseURL: 'todo',
    )
        : const FirebaseOptions(
      googleAppID: '###',
      apiKey: '###',
      databaseURL: 'https://###.firebaseio.com',
    ),
  );
  runApp(new MyApp(app));
}

class MyApp extends StatelessWidget {
  MyApp(this.app);

  final FirebaseApp app;

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Events app',
      theme: new ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or press Run > Flutter Hot Reload in IntelliJ). Notice that the
        // counter didn't reset back to zero; the application is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Events Demo Home Page', app: app),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title, this.app}) : super(key: key);

  final FirebaseApp app;
  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  DatabaseReference _counterRef;
  StreamSubscription<Event> _counterSubscription;
  DatabaseError _error;

  @override
  void initState() {
    super.initState();
    final FirebaseDatabase database = new FirebaseDatabase(app: widget.app);
    database.setPersistenceEnabled(true);
    database.setPersistenceCacheSizeBytes(10000000);
    print("!!!");
    _counterRef = database.reference().child('test');
    _counterRef.keepSynced(true);
    _counterSubscription = _counterRef.onValue.listen((Event event) {
      setState(() {
        _error = null;
        _counter = event.snapshot.value;
        print("Counter " + _counter.toString());

      });
    }, onError: (Object o) {
      final DatabaseError error = o;
      setState(() {
        _error = error;
      });
    });
  }

  void _increment() async {
    print("increment");
    // Increment counter in transaction.
    final TransactionResult transactionResult =
    await _counterRef.runTransaction((MutableData mutableData) async {
      mutableData.value = (mutableData.value ?? 0) + 1;
      return mutableData;
    });

    if (transactionResult.committed) {
      print('Transaction commited');
    } else {
      print('Transaction not committed.');
      if (transactionResult.error != null) {
        print(transactionResult.error.message);
      }
    }
  }

  @override
  void dispose() {
    _counterSubscription.cancel();
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return new Scaffold(
      appBar: new AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: new Text(widget.title),
      ),
      body: new Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: new Column(
          // Column is also layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug paint" (press "p" in the console where you ran
          // "flutter run", or select "Toggle Debug Paint" from the Flutter tool
          // window in IntelliJ) to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new Text(
              'You have pushed the button this many times:',
            ),
            new Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _increment,
        tooltip: 'Increment',
        child: new Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

pubspec.yaml

name: events
description: Events app

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.0

  firebase_core: ^0.2.3
  firebase_database: ^0.4.5
  firebase_auth: ^0.5.5
  google_sign_in: ^3.0.2

dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true