Declaratively switch child widgets based on the current `Router` location.

Using scheduleMiscrotask in initState is a very very very bad idea!

Instead of https://github.com/gskinnerTeam/flutter-routed-widget-switcher/blob/master/lib/routed_widget_switcher.dart#L41-L46 you may:

@override
void didChangeDependencies() {
  delegate ??= Router.of(context).routerDelegate..addListener(_handleRouteChanged);
  provider ??= Router.of(context).routeInformationProvider..addListener(_handleRouteChanged);
  super.didChangeDependencies();
}

But anyway, is a bad idea to do what you do that way

Just use AnimatedBuilder, like that:

class YourWidget extends StatelessWidget {
   @override
   Widget build(_) => AnimatedBuilder(
      animation: Listenable.merge(<Listenable>[
        Router.of(context).routerDelegate,
        Router.of(context).routeInformationProvider,
      ]),
      builder: ...
   );
}

When running the integration test in the example folder, I get this failure :

00:00 +0: VRouter
[VRouter: INFO] Successfully navigated to "/" using VRouter.to o
[VRouter: INFO] Successfully navigated to "/dashboard" using VRouter.to o
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following TestFailure object was thrown running a test:
  Expected: exactly one matching node in the widget tree
  Actual: _WidgetTypeFinder:<zero widgets with type "DashboardMenu" (ignoring offstage widgets)>
   Which: means none were found but one was expected

As you can see, the Sidebar doesn't react to the route changes.

Here is a simplified example where you can verify that it's indeed not working : (Press on the FAB to go to a random path)

import 'dart:math';

import 'package:flutter/material.dart';
import 'package:routed_widget_switcher/routed_widget_switcher.dart';
import 'package:vrouter/vrouter.dart';

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

class VRouterApp extends StatelessWidget {
  const VRouterApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return VRouter(
        builder: (_, navigator) {
          // Wrap the navigator in a simple scaffold, with a persistent `SideBar` on the left
          return Row(
            children: [
              const SideBar(),
              Expanded(child: navigator),
            ],
          );
        },
        routes: [
          VWidget.builder(
            path: '*',
            builder: (_, data) => MainScaffold(data.url ?? ''),
          ),
        ]);
  }
}

class SideBar extends StatelessWidget {
  const SideBar({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    Widget buildSideBarBg(Widget child) =>
        Material(child: SizedBox(width: 180, child: child));
    return buildSideBarBg(
      RoutedSwitcher(
        builders: (info) {
          // PROBLEM : Always prints '/'
          print(info.url);
          return [
            // Wildcard will match any route
            Routed('*', MainMenu.new),
            Routed('/dashboard', DashboardMenu.new),
            Routed('/settings', SettingsMenu.new),
          ];
        },
      ),
    );
  }
}

class MainScaffold extends StatelessWidget {
  final String location;

  static const paths = [
    '/',
    '/pageA',
    '/pageB',
    '/dashboard',
    '/dashboard/foo',
    '/dashboard/bar',
    '/settings',
    '/settings/foo',
    '/settings/bar',
  ];

  static final random = Random();

  const MainScaffold(this.location, {Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        floatingActionButton: FloatingActionButton(
          onPressed: () {
            final int i = random.nextInt(9);

            context.vRouter.to(paths[i]);
          },
        ),
        body: SafeArea(
          child: Center(child: Text(location)),
        ));
  }
}

/// Stub
class MainMenu extends StatelessWidget {
  MainMenu({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => Container(
        color: Colors.red,
        child: const Center(
          child: Text('MAIN MENU'),
        ),
      );
}

/// Stub
class DashboardMenu extends StatelessWidget {
  DashboardMenu({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => Container(
        color: Colors.blue,
        child: const Center(
          child: Text('DASHBOARD\nMENU'),
        ),
      );
}

/// Stub
class SettingsMenu extends StatelessWidget {
  SettingsMenu({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => Container(
        color: Colors.green,
        child: const Center(
          child: Text('SETTINGS MENU'),
        ),
      );
}