Flutter Snackbar

import 'package:flutter/material.dart';  
  
void main() {runApp(MyApp());}  
  
class MyApp extends StatelessWidget {  
  @override  
  Widget build(BuildContext context) {  
    return MaterialApp(  
      theme: new ThemeData(  
        primaryColor: const Color(0xFF43a047),  
        accentColor: const Color(0xFFffcc00),  
        primaryColorBrightness: Brightness.dark,  
      ),  
      home: Scaffold(  
        appBar: AppBar(  
          title: Text('Flutter SnackBar Demo'),  
        ),  
        body: SnackBarPage(),  
      ),  
    );  
  }  
}  
  
class SnackBarPage extends StatelessWidget {  
  @override  
  Widget build(BuildContext context) {  
    return Center(  
      child: RaisedButton(  
        child: Text('Show SnackBar', style: TextStyle(fontSize: 25.0),),  
        textColor: Colors.white,  
        color: Colors.redAccent,  
        padding: EdgeInsets.all(8.0),  
        splashColor: Colors.grey,  
        onPressed: () {  
          final snackBar = SnackBar(  
            content: Text('Hey! This is a SnackBar message.'),  
            duration: Duration(seconds: 5),  
            action: SnackBarAction(  
              label: 'Undo',  
              onPressed: () {  
              },  
            ),  
          );  
          Scaffold.of(context).showSnackBar(snackBar);  
        },  
      ),  
    );  
  }  
}