Migrate veggieseasons to go_router (#1544)

* add go_router

* wip migration to go_router

* small fixes

* home screen cleanup

* remove unused

* small fixes

* details should be fullscreen dialog

* remove comment

* fix navigation outside the shell by using the correct navigation keys

* add restoration id to all pages

* test passing, but parts are commented out, wip

* uncommented more test code

* Add TODOs

* fix lint issues

* fix tests

* use FadeTransitionPage

* remove unnecessary builders

* FadeTransitionPage same as CustomTransitionPage

* add comments regarding relative routes

* add missing pageKey

* add missing const

---------

Co-authored-by: Brett Morgan <brettmorgan@google.com>

veggieseasons/lib/widgets/fade_transition_page.dart

@@ -0,0 +1,66 @@
+// Copyright 2021, the Flutter 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/cupertino.dart';
+
+class FadeTransitionPage<T> extends Page<T> {
+  final Widget child;
+  final Duration duration;
+
+  const FadeTransitionPage({
+    super.key,
+    required this.child,
+    this.duration = const Duration(milliseconds: 300),
+    super.restorationId,
+  });
+
+  @override
+  Route<T> createRoute(BuildContext context) =>
+      PageBasedFadeTransitionRoute<T>(this);
+}
+
+class PageBasedFadeTransitionRoute<T> extends PageRoute<T> {
+  PageBasedFadeTransitionRoute(FadeTransitionPage<T> page)
+      : super(settings: page);
+
+  FadeTransitionPage<T> get _page => settings as FadeTransitionPage<T>;
+
+  @override
+  Color? get barrierColor => null;
+
+  @override
+  String? get barrierLabel => null;
+
+  @override
+  Duration get transitionDuration => _page.duration;
+
+  @override
+  Duration get reverseTransitionDuration => _page.duration;
+
+  @override
+  bool get maintainState => true;
+
+  @override
+  Widget buildPage(
+    BuildContext context,
+    Animation<double> animation,
+    Animation<double> secondaryAnimation,
+  ) {
+    return _page.child;
+  }
+
+  @override
+  Widget buildTransitions(
+    BuildContext context,
+    Animation<double> animation,
+    Animation<double> secondaryAnimation,
+    Widget child,
+  ) {
+    final tween = CurveTween(curve: Curves.easeInOut);
+    return FadeTransition(
+      opacity: animation.drive(tween),
+      child: _page.child,
+    );
+  }
+}

veggieseasons/lib/widgets/veggie_card.dart

@@ -5,8 +5,8 @@
 import 'dart:ui';
 
 import 'package:flutter/cupertino.dart';
+import 'package:go_router/go_router.dart';
 import 'package:veggieseasons/data/veggie.dart';
-import 'package:veggieseasons/screens/details.dart';
 import 'package:veggieseasons/styles.dart';
 
 class FrostyBackground extends StatelessWidget {
@@ -139,7 +139,12 @@ class VeggieCard extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return PressableCard(
-      onPressed: () => DetailsScreen.show(Navigator.of(context), veggie.id),
+      onPressed: () {
+        // GoRouter does not support relative routes,
+        // so navigate to the absolute route.
+        // see https://github.com/flutter/flutter/issues/108177
+        context.go('/list/details/${veggie.id}');
+      },
       child: Stack(
         children: [
           Semantics(

veggieseasons/lib/widgets/veggie_headline.dart

@@ -3,8 +3,8 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
+import 'package:go_router/go_router.dart';
 import 'package:veggieseasons/data/veggie.dart';
-import 'package:veggieseasons/screens/details.dart';
 import 'package:veggieseasons/styles.dart';
 
 class ZoomClipAssetImage extends StatelessWidget {
@@ -72,7 +72,13 @@ class VeggieHeadline extends StatelessWidget {
     final themeData = CupertinoTheme.of(context);
 
     return GestureDetector(
-      onTap: () => DetailsScreen.show(Navigator.of(context), veggie.id),
+      onTap: () {
+        // GoRouter does not support relative routes,
+        // so navigate to the absolute route, which can be either
+        // `/favorites/details/${veggie.id}` or `/search/details/${veggie.id}`
+        // see https://github.com/flutter/flutter/issues/108177
+        context.go('${GoRouter.of(context).location}/details/${veggie.id}');
+      },
       child: Row(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [