Introduces the BottomAppBar widget

Scaffold_BottomAppBar.dart

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

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

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);
  State createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  int _count = 0;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(
          title: Text('Sample Code'),
        ),
        body: Center(
          child: Text('You have pressed the button $_count times.'),
        ),
        bottomNavigationBar: BottomAppBar(
          shape: CircularNotchedRectangle(),
          notchMargin: 4.0,
          child: Row(
            mainAxisSize: MainAxisSize.max,
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              IconButton(
                icon: Icon(Icons.menu),
                onPressed: () {},
              ),
              IconButton(
                icon: Icon(Icons.search),
                onPressed: () {},
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => setState(() {
                _count++;
              }),
          tooltip: 'Increment Counter',
          child: Icon(Icons.add),
        ),
        floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      ),
    );
  }
}