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lib/13/go/others/state_restoration.dart

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+// Copyright 2013 The Flutter Authors. 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';
+import 'package:go_router/go_router.dart';
+
+void main() => runApp(
+      const RootRestorationScope(restorationId: 'root', child: App()),
+    );
+
+/// The main app.
+class App extends StatefulWidget {
+  /// Creates an [App].
+  const App({super.key});
+
+  /// The title of the app.
+  static const String title = 'GoRouter Example: State Restoration';
+
+  @override
+  State<App> createState() => _AppState();
+}
+
+class _AppState extends State<App> with RestorationMixin {
+  @override
+  String get restorationId => 'wrapper';
+
+  @override
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
+    // Implement restoreState for your app
+  }
+
+  @override
+  Widget build(BuildContext context) => MaterialApp.router(
+        routerConfig: _router,
+        title: App.title,
+        restorationScopeId: 'app',
+      );
+
+  final GoRouter _router = GoRouter(
+    routes: <GoRoute>[
+      // restorationId set for the route automatically
+      GoRoute(
+        path: '/',
+        builder: (BuildContext context, GoRouterState state) =>
+            const Page1Screen(),
+      ),
+
+      // restorationId set for the route automatically
+      GoRoute(
+        path: '/page2',
+        builder: (BuildContext context, GoRouterState state) =>
+            const Page2Screen(),
+      ),
+    ],
+    restorationScopeId: 'router',
+  );
+}
+
+/// The screen of the first page.
+class Page1Screen extends StatelessWidget {
+  /// Creates a [Page1Screen].
+  const Page1Screen({super.key});
+
+  @override
+  Widget build(BuildContext context) => Scaffold(
+        appBar: AppBar(title: const Text(App.title)),
+        body: Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: <Widget>[
+              ElevatedButton(
+                onPressed: () => context.go('/page2'),
+                child: const Text('Go to page 2'),
+              ),
+            ],
+          ),
+        ),
+      );
+}
+
+/// The screen of the second page.
+class Page2Screen extends StatelessWidget {
+  /// Creates a [Page2Screen].
+  const Page2Screen({super.key});
+
+  @override
+  Widget build(BuildContext context) => Scaffold(
+        appBar: AppBar(title: const Text(App.title)),
+        body: Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: <Widget>[
+              ElevatedButton(
+                onPressed: () => context.go('/'),
+                child: const Text('Go to home page'),
+              ),
+            ],
+          ),
+        ),
+      );
+}