import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: SemanticsNav1HomePage(),
    );
  }
}

class SemanticsNav1HomePage extends StatelessWidget {

  @override
  Widget build(BuildContext context) {

    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);

    return Semantics(
      scopesRoute: true,
      namesRoute: true,
      label: "Page 1",
      explicitChildNodes: true,
      child: Scaffold(
        body: SafeArea(
          top: true,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            mainAxisSize: MainAxisSize.max,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.all(24.0),
                child: Text(
                  "Hello, press the button below to launch the next page",
                  style: TextStyle(fontSize: 24),
                ),
              ),
              Expanded(
                child: Center(
                  child: MaterialButton(
                      color: Colors.black,
                      textColor: Colors.white,
                      child: Text("Launch route 2", style: TextStyle(fontSize: 20)),
                      onPressed: () => Navigator.push(context, PageRouteBuilder(pageBuilder: (context, animation, secondaryAnimation) => SemanticsNav2HomePage())),
                  )
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class SemanticsNav2HomePage extends StatelessWidget {

  @override
  Widget build(BuildContext context) {

    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);

    return Semantics(
      scopesRoute: true,
      namesRoute: true,
      label: "Page 2",
      explicitChildNodes: true,
      child: Scaffold(
        body: SafeArea(
          top: true,
          child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
            mainAxisSize: MainAxisSize.max,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.all(24.0),
                child: Text(
                  "Hello, press the button below to close this page",
                  style: TextStyle(fontSize: 24),
                ),
              ),
              Expanded(
                child: Center(
                    child: MaterialButton(
                      color: Colors.black,
                      textColor: Colors.white,
                      child: Text("Pop route 2", style: TextStyle(fontSize: 20)),
                        onPressed: () => Navigator.pop(context),
                    )
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}