bottom navigation bar in flutter

main.dart

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: MyPage(),
    );
  }
}

class MyPage extends StatefulWidget {
  @override
  _MyPageState createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> {
  String page = "";
  GlobalKey _bottomNavigationKey = GlobalKey();
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      bottomNavigationBar: CurvedNavigationBar(
          key: _bottomNavigationKey,
          items: <Widget>[
            Icon(Icons.category, size: 30),
            Icon(Icons.business_center, size: 30),
            Icon(Icons.person, size: 30),
          ],
          onTap: (index) {
            setState(() {
              switch (index) {
                case 0:
                  page = "Welcome to Category";
                  break;
                case 1:
                  page = "Welcome to Business";
                  break;
                case 2:
                  page = "Welcome to Profile";
                  break;
                default:
                  page = "Welcome";
              }
            });
          }),
      body: Container(
          color: Colors.blueAccent,
          child: Center(
            child: Container(
              child: Text(page),
            ),
          )),
    );
  }
}