main.dart

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      routeInformationParser: MyRouteInformationParser(),
      routerDelegate: MyRouterDelegate(),
    );
  }
}

class MyHomePage extends StatefulWidget {

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          "Home"
        ),
      ),
      body: Center(
        child: Text(
          "this is home page"
        ),
      ),
      floatingActionButton: FloatingActionButton(
        child: Icon(
          Icons.add,
        ),
        onPressed: () {
          MyRouterDelegate.of(context).pushNamed("/first");
        },
      ),
    );
  }
}


class MyRouteInformationParser extends RouteInformationParser<RouteSettings> {
  @override
  Future<RouteSettings> parseRouteInformation(RouteInformation routeInformation) {
    print("name: ${routeInformation.location}");
    return SynchronousFuture(RouteSettings(
      name: routeInformation.location
    ));
  }

}

class MyRouterDelegate extends RouterDelegate<RouteSettings>
    with ChangeNotifier {

  MyRouterDelegate() : navigatorKey = GlobalKey<NavigatorState>();

  final _pages = <MyPage>[];

  final GlobalKey<NavigatorState> navigatorKey;

  static MyRouterDelegate of(BuildContext context) {
    RouterDelegate routerDelegate = Router.of(context).routerDelegate;
    assert(routerDelegate is MyRouterDelegate);
    return routerDelegate as MyRouterDelegate;
  }

  @override
  Widget build(BuildContext context) {
    return Navigator(
      key: navigatorKey,
      pages: List.of(_pages),
      onPopPage: (route, result) {
        if (_pages.length > 1 && route.settings is MyPage) {
          final MyPage<dynamic>? removed = _pages.lastWhere(
                (element) => element.name == route.settings.name,
          );
          if (removed != null) {
            _pages.remove(removed);
            notifyListeners();
          }
        }

        return route.didPop(result);
      },
    );
  }

  @override
  Future<bool> popRoute() {
    print("popRoute");
    final NavigatorState? navigator = navigatorKey.currentState;
    if (navigator == null)
      return SynchronousFuture<bool>(false);
    return navigator.maybePop();
  }

  @override
  Future<void> setNewRoutePath(configuration) {
    print("setNewRoutePath");
    _pages.add(getRoutePage(
        name: configuration.name!,
        arguments: configuration.arguments as Map<String, dynamic>?));
    return SynchronousFuture<void>(null);
  }

  Future<T?> pushNamed<T extends Object?>(String routeName, {
    Map<String, dynamic>? arguments,
  }) {
    print("pushNamed: routeName: $routeName");

    MyPage<T?> page = getRoutePage(name: routeName, arguments: arguments);

    _pages.add(page);
    notifyListeners();
    return page.popped;
  }

  MyPage<T?> getRoutePage<T extends Object?>({
    required String name,
    Map<String, dynamic>? arguments,
  }) {
    MyRouteSettings routeSettings = getRouteSettings(name: name, arguments: arguments);

    MyPage<T?> page = MyPage(
        key: UniqueKey(),
        name: routeSettings.name ?? '',
        widget: routeSettings.widget ?? Container(),
        arguments: routeSettings.arguments);
    return page;
  }
}

class MyRouteSettings extends RouteSettings {
  const MyRouteSettings({
    required String name,
    Object? arguments,
    this.widget,
    this.showStatusBar,
    this.routeName,
    // this.pageRouteType,
    // this.description,
    // this.exts,
  }) : super(
    name: name,
    arguments: arguments,
  );

  /// The Widget base on this route
  final Widget? widget;

  /// Whether show status bar.
  final bool? showStatusBar;

  /// The route name to track page
  final String? routeName;


}
  
class MyPage<T> extends Page<T> {

  MyPage({
    required String name,
    required LocalKey key,
    required this.widget,
    Object? arguments,
    // this.showStatusBar,
    // this.routeName,
    // this.pageRouteType,
    // this.description,
    // this.exts,
  }) : super(
    key: key,
    name: name,
    arguments: arguments,
  );

  final Widget widget;

  Future<T> get popped => _popCompleter.future;
  final Completer<T> _popCompleter = Completer<T>();
  bool get isCompleted => _popCompleter.isCompleted;

  @override
  Route<T> createRoute(BuildContext context) {
    final Route<T> route = MaterialPageRoute(
      settings: this,
      builder: (BuildContext context) => widget,
    );
    return route
      ..popped.then((T? value) {
        if (!isCompleted) {
          _popCompleter.complete(value);
        }
      });
  }
}
  
MyRouteSettings getRouteSettings ({
  required String name,
  Map<String, dynamic>? arguments,
}) {
  final Map<String, dynamic> safeArguments =
      arguments ?? const <String, dynamic>{};
  switch (name) {
    case '/':
      return MyRouteSettings(
        name: name,
        arguments: arguments,
        widget: MyHomePage(),
      );
    case '/first':
      return MyRouteSettings(
        name: name,
        arguments: arguments,
        widget: FirstPage(),
      );
    case '/second':
      return MyRouteSettings(
        name: name,
        arguments: arguments,
        widget: SecondPage(),
      );
    default:
      return const MyRouteSettings(name: '404');
  }
}
  
class FirstPage extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          "First Page"
        ),
      ),
      body: Center(
        child: Text(
          "this is the first page"
        ),
      ),
      floatingActionButton: FloatingActionButton(
        child: Icon(
          Icons.arrow_circle_up,
        ),
        onPressed: () {

        },
      ),
    );
  }

}
  
class SecondPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
            "Second Page"
        ),
      ),
      body: Center(
        child: Text(
            "this is the second page"
        ),
      ),
    );
  }

}