Navigation -Introduction to flutter

main.dart

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. 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(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: NavigationTest(),
    );
  }
}

class NavigationTest extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Home page"),
      ),
      body: Container(
        color: Colors.red,
        child: Center(
          child: GestureDetector(
            onTap: () {
              Navigator.of(context)
                  .push(MaterialPageRoute(builder: (_) => PushedWidgetTest()));
            },
            child: Text(
              "Click to push new page on navigation stack",
            ),
          ),
        ),
      ),
    );
  }
}

class PushedWidgetTest extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Pushed Route"),
      ),
      body: Container(
        color: Colors.blue,
        child: Center(
          child: GestureDetector(
            onTap: () {
              Navigator.of(context).pushReplacement(
                MaterialPageRoute(
                  builder: (_) => ReplaceWidgetTest(
                    title: "Push and Replaced Route",
                  ),
                ),
              );
            },
            child: Text(
              "Click to push a replacement",
            ),
          ),
        ),
      ),
    );
  }
}

class ReplaceWidgetTest extends StatelessWidget {
  final String title;
  ReplaceWidgetTest({@required this.title});
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(this.title),
      ),
      body: Container(
        color: Colors.green,
        child: Center(
          child: GestureDetector(
            onTap: () {
              Navigator.of(context).pop();
            },
            child: Text(
              "Click to pop this page",
            ),
          ),
        ),
      ),
    );
  }
}

class DynamicWidget extends StatefulWidget {
  createState() => _DynamicWidgetState();
}

class _DynamicWidgetState extends State<DynamicWidget>{
  Color color = Colors.red;
  String text = "Click to change color to green";
   Widget build(BuildContext context){
    return Scaffold(
      appBar: AppBar(title: Text("Stateful Widget")),
      body: Container(
        color: color,
        child: Center(
          child: GestureDetector(
            onTap: () {
              setState((){
                color = Colors.green;
                text = "Color is now green";
              });
            },
            child: Text(
              text,
            ),
          ),
        ),
      ),
    );
  }
}