How to use BottomNavigationBar with Navigator?

Question

The Flutter Gallery example of BottomNavigationBar uses a Stack of FadeTransitions in the body of the Scaffold.

I

Answer 1

Here is an example how you can use Navigator with BottomNavigationBar to navigate different screen.

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      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 {
  // This navigator state will be used to navigate different pages
  final GlobalKey _navigatorKey = GlobalKey();
  int _currentTabIndex = 0;

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        body: Navigator(key: _navigatorKey, onGenerateRoute: generateRoute),
        bottomNavigationBar: _bottomNavigationBar(),
      ),
    );
  }

  Widget _bottomNavigationBar() {
    return BottomNavigationBar(
      type: BottomNavigationBarType.fixed,
      items: [
        BottomNavigationBarItem(
          icon: Icon(Icons.home),
          title: Text("Home"),
        ),
        BottomNavigationBarItem(
            icon: Icon(Icons.account_circle), title: Text("Account")),
        BottomNavigationBarItem(
          icon: Icon(Icons.settings),
          title: Text("Settings"),
        )
      ],
      onTap: _onTap,
      currentIndex: _currentTabIndex,
    );
  }

  _onTap(int tabIndex) {
    switch (tabIndex) {
      case 0:
        _navigatorKey.currentState.pushReplacementNamed("Home");
        break;
      case 1:
        _navigatorKey.currentState.pushReplacementNamed("Account");
        break;
      case 2:
        _navigatorKey.currentState.pushReplacementNamed("Settings");
        break;
    }
    setState(() {
      _currentTabIndex = tabIndex;
    });
  }

  Route generateRoute(RouteSettings settings) {
    switch (settings.name) {
      case "Account":
        return MaterialPageRoute(builder: (context) => Container(color: Colors.blue,child: Center(child: Text("Account"))));
      case "Settings":
        return MaterialPageRoute(builder: (context) => Container(color: Colors.green,child: Center(child: Text("Settings"))));
      default:
        return MaterialPageRoute(builder: (context) => Container(color: Colors.white,child: Center(child: Text("Home"))));
    }
  }
}