Circular Notched Rectangle With Example In Flutter Using Android

floatingActionButton: new FloatingActionButton.extended(
  onPressed: _incrementCounter,
  tooltip: 'Increment',
  icon: new Icon(Icons.add),
  label: const Text("Add",),
  backgroundColor: Colors.red,
),
floatingActionButtonLocation: FloatingActionButtonLocation.endDocked,
bottomNavigationBar: BottomAppBar(
  clipBehavior: Clip.antiAlias,
  color: Colors.blue,
  shape: CircularNotchedRectangle(),
  child: Material(
    child: SizedBox(width: double.infinity, height: 80.0,),
    color: Colors.red,
  ),
),

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowMaterialGrid: false,
      title: 'Flutter Demo',

      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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


  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {

    return new Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        title: new Text('Circular Notched Rectangle'),
        backgroundColor: Colors.red,
      ),
      body: new Center(
        child: new Column(
          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.extended(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        icon: new Icon(Icons.add),
        label: const Text("Add",),
        backgroundColor: Colors.red,
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.endDocked,
      bottomNavigationBar: BottomAppBar(
        clipBehavior: Clip.antiAlias,
        color: Colors.blue,
        shape: CircularNotchedRectangle(),
        child: Material(
          child: SizedBox(width: double.infinity, height: 80.0,),
          color: Colors.red,
        ),
      ),
    );
  }
}