How To Create Popup Menu Bottom Nav Bar Using Flutter App

import 'package:flutter/material.dart';

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Transform',
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String text = 'Home';

  _onTap(int index) async {
    switch (index) {
      case 0:
        setState(() => text = 'Home');
        break;
      case 1:
        setState(() => text = 'Favorite');
        break;
      case 2:
        setState(() => text = 'Profile');
        break;
      case 3:
        setState(() => text = 'Settings');
        await showMenu(
          context: context,
          position: RelativeRect.fromLTRB(1000.0, 1000.0, 0.0, 0.0),
          items: [
            PopupMenuItem(
              child: Text("Bajarangisoft.com"),
            ),
            PopupMenuItem(
              child: Text("Yahoo.com"),
            ),
            PopupMenuItem(
              child: Text("Google.com"),
            ),
          ],
          elevation: 8.0,
        );
        break;
      default:
        setState(() => text = 'Home');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.cyan,
        title: Text("PopupMenu Bottom Nav Bar"),
      ),
      body: Center(
        child: Text(text,
            style: TextStyle(
              fontSize: 20,
              fontWeight: FontWeight.bold,
            )),
      ),
      bottomNavigationBar: BottomNavigationBar(
        backgroundColor: Colors.cyan,
        type: BottomNavigationBarType.fixed,
        currentIndex: 0,
        items: <BottomNavigationBarItem>[
          BottomNavigationBarItem(

            icon: Icon(Icons.home,color: Colors.white,),
            title: Text("Home",style: TextStyle(color: Colors.white),),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.favorite,color: Colors.white,),
            title: Text("Favorite",style: TextStyle(color: Colors.white),),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.person,color: Colors.white,),
            title: Text("Profile",style: TextStyle(color: Colors.white),),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.add,color: Colors.white,),
            title: Text("More",style: TextStyle(color: Colors.white),),
          ),
        ],
        onTap: _onTap,
      ),
    );
  }
}