Flutter:  Routing and Navigator 

Mobile apps typically display full-screen elements called “screens” or “pages”. In Flutter these elements are called routes and they’re managed by a Navigator widget.

METHOD 1

PLEASE DEFINE ALSO widget_test.dart

void main() {
  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
    // Build our app and trigger a frame.    await tester.pumpWidget(HomePage());

    // Verify that our counter starts at 0.    expect(find.text('0'), findsOneWidget);
    expect(find.text('1'), findsNothing);

    // Tap the '+' icon and trigger a frame.    await tester.tap(find.byIcon(Icons.add));
    await tester.pump();

    // Verify that our counter has incremented.    expect(find.text('0'), findsNothing);
    expect(find.text('1'), findsOneWidget);
  });
}

import 'package:flutter/material.dart';

void main() {
runApp(MaterialApp(
home: HomePage(),
));
}

class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Home'),
),
body: new Center(
child: RaisedButton(
onPressed: () {
Route route = MaterialPageRoute(builder: (context) => SecondHome());
Navigator.push(context, route);
},
child: Text('Second Home Welcome'),
),
),
);
}
}

class SecondHome extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Second Hoem'),
),
body: new Center(
child: RaisedButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Go Back'),
),
),
);
}
}

METHOD 2

// Copyright 2018 The Flutter team. All rights reserved.// Use of this source code is governed by a BSD-style license that can be// found in the LICENSE file.
import 'package:flutter/material.dart';
void main() {
  runApp(MaterialApp(
    initialRoute: '/',
    routes: <String, WidgetBuilder>{
      '/': (context) => HomePage(),
      '/second': (context) => SecondHome(),
    },



  ));
}

class HomePage extends StatelessWidget {
  @override  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: new Center(
        child: RaisedButton(
          onPressed: () {
         /*   Route route = MaterialPageRoute(builder: (context) => SecondHome());  //MaterialPageRoute is responsible for page Transition            Navigator.push(context, route);  //Navigator maintain Stack-based history of routes*/
            Navigator.pushNamed(context, '/second');
          },
          child: Text('Second Home'),
        ),
      ),
    );
  }
}

class SecondHome extends StatelessWidget {
  @override  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Second Hoem'),
      ),
      body: new Center(
        child: RaisedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: Text('Go Back'),
        ),
      ),
    );
  }
}