snapshot of https://github.com/flutter/samples.git (main, 2026-09-16; blobs > 131072B omitted)

compass_app/app/lib/ui/results/view_models/results_viewmodel.dart

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+// Copyright 2024 The Flutter team. 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';
+import 'package:logging/logging.dart';
+
+import '../../../data/repositories/destination/destination_repository.dart';
+import '../../../data/repositories/itinerary_config/itinerary_config_repository.dart';
+import '../../../domain/models/destination/destination.dart';
+import '../../../domain/models/itinerary_config/itinerary_config.dart';
+import '../../../utils/command.dart';
+import '../../../utils/result.dart';
+
+/// Results screen view model
+/// Based on https://docs.flutter.dev/get-started/fwe/state-management#using-mvvm-for-your-applications-architecture
+class ResultsViewModel extends ChangeNotifier {
+  ResultsViewModel({
+    required DestinationRepository destinationRepository,
+    required ItineraryConfigRepository itineraryConfigRepository,
+  }) : _destinationRepository = destinationRepository,
+       _itineraryConfigRepository = itineraryConfigRepository {
+    updateItineraryConfig = Command1<void, String>(_updateItineraryConfig);
+    search = Command0(_search)..execute();
+  }
+
+  final _log = Logger('ResultsViewModel');
+
+  final DestinationRepository _destinationRepository;
+
+  final ItineraryConfigRepository _itineraryConfigRepository;
+
+  // Setters are private
+  List<Destination> _destinations = [];
+
+  /// List of destinations, may be empty but never null
+  List<Destination> get destinations => _destinations;
+
+  ItineraryConfig? _itineraryConfig;
+
+  /// Filter options to display on search bar
+  ItineraryConfig get config => _itineraryConfig ?? const ItineraryConfig();
+
+  /// Perform search
+  late final Command0 search;
+
+  /// Store ViewModel data into [ItineraryConfigRepository] before navigating.
+  late final Command1<void, String> updateItineraryConfig;
+
+  Future<Result<void>> _search() async {
+    // Load current itinerary config
+    final resultConfig = await _itineraryConfigRepository.getItineraryConfig();
+    switch (resultConfig) {
+      case Error<ItineraryConfig>():
+        _log.warning(
+          'Failed to load stored ItineraryConfig',
+          resultConfig.error,
+        );
+        return resultConfig;
+      case Ok<ItineraryConfig>():
+    }
+    _itineraryConfig = resultConfig.value;
+    notifyListeners();
+
+    final result = await _destinationRepository.getDestinations();
+    switch (result) {
+      case Ok():
+        {
+          // If the result is Ok, update the list of destinations
+          _destinations = result.value
+              .where(
+                (destination) =>
+                    destination.continent == _itineraryConfig!.continent,
+              )
+              .toList();
+          _log.fine('Destinations (${_destinations.length}) loaded');
+        }
+      case Error():
+        {
+          _log.warning('Failed to load destinations', result.error);
+        }
+    }
+
+    // After finish loading results, notify the view
+    notifyListeners();
+    return result;
+  }
+
+  Future<Result<void>> _updateItineraryConfig(String destinationRef) async {
+    assert(destinationRef.isNotEmpty, "destinationRef should not be empty");
+
+    final resultConfig = await _itineraryConfigRepository.getItineraryConfig();
+    switch (resultConfig) {
+      case Error<ItineraryConfig>():
+        _log.warning(
+          'Failed to load stored ItineraryConfig',
+          resultConfig.error,
+        );
+        return resultConfig;
+      case Ok<ItineraryConfig>():
+    }
+
+    final itineraryConfig = resultConfig.value;
+    final result = await _itineraryConfigRepository.setItineraryConfig(
+      itineraryConfig.copyWith(destination: destinationRef, activities: []),
+    );
+    if (result is Error) {
+      _log.warning('Failed to store ItineraryConfig', result.error);
+    }
+    return result;
+  }
+}

compass_app/app/lib/ui/results/widgets/result_card.dart

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+// Copyright 2024 The Flutter team. 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:cached_network_image/cached_network_image.dart';
+import 'package:flutter/material.dart';
+import 'package:google_fonts/google_fonts.dart';
+import '../../../domain/models/destination/destination.dart';
+import '../../../utils/image_error_listener.dart';
+import '../../core/ui/tag_chip.dart';
+
+class ResultCard extends StatelessWidget {
+  const ResultCard({super.key, required this.destination, required this.onTap});
+
+  final Destination destination;
+  final GestureTapCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return ClipRRect(
+      borderRadius: BorderRadius.circular(10.0),
+      child: Stack(
+        fit: StackFit.expand,
+        children: [
+          CachedNetworkImage(
+            imageUrl: destination.imageUrl,
+            fit: BoxFit.fitHeight,
+            errorWidget: (context, url, error) => const Icon(Icons.error),
+            errorListener: imageErrorListener,
+          ),
+          Positioned(
+            bottom: 12.0,
+            left: 12.0,
+            right: 12.0,
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Text(destination.name.toUpperCase(), style: _cardTitleStyle),
+                const SizedBox(height: 6),
+                Wrap(
+                  spacing: 4.0,
+                  runSpacing: 4.0,
+                  direction: Axis.horizontal,
+                  children: destination.tags
+                      .map((e) => TagChip(tag: e))
+                      .toList(),
+                ),
+              ],
+            ),
+          ),
+          // Handle taps
+          Positioned.fill(
+            child: Material(
+              color: Colors.transparent,
+              child: InkWell(onTap: onTap),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+final _cardTitleStyle = GoogleFonts.rubik(
+  textStyle: const TextStyle(
+    fontWeight: FontWeight.w800,
+    fontSize: 15.0,
+    color: Colors.white,
+    letterSpacing: 1,
+    shadows: [
+      // Helps to read the text a bit better
+      Shadow(blurRadius: 3.0, color: Colors.black),
+    ],
+  ),
+);

compass_app/app/lib/ui/results/widgets/results_screen.dart

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+// Copyright 2024 The Flutter team. 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';
+
+import '../../../routing/routes.dart';
+import '../../core/localization/applocalization.dart';
+import '../../core/themes/dimens.dart';
+import '../../core/ui/error_indicator.dart';
+import '../../core/ui/search_bar.dart';
+import '../view_models/results_viewmodel.dart';
+import 'result_card.dart';
+
+class ResultsScreen extends StatefulWidget {
+  const ResultsScreen({super.key, required this.viewModel});
+
+  final ResultsViewModel viewModel;
+
+  @override
+  State<ResultsScreen> createState() => _ResultsScreenState();
+}
+
+class _ResultsScreenState extends State<ResultsScreen> {
+  @override
+  void initState() {
+    super.initState();
+    widget.viewModel.updateItineraryConfig.addListener(_onResult);
+  }
+
+  @override
+  void didUpdateWidget(covariant ResultsScreen oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    oldWidget.viewModel.updateItineraryConfig.removeListener(_onResult);
+    widget.viewModel.updateItineraryConfig.addListener(_onResult);
+  }
+
+  @override
+  void dispose() {
+    widget.viewModel.updateItineraryConfig.removeListener(_onResult);
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return PopScope(
+      canPop: false,
+      onPopInvokedWithResult: (didPop, r) {
+        if (!didPop) context.go(Routes.search);
+      },
+      child: Scaffold(
+        body: ListenableBuilder(
+          listenable: widget.viewModel.search,
+          builder: (context, child) {
+            if (widget.viewModel.search.completed) {
+              return child!;
+            }
+            return Column(
+              children: [
+                _AppSearchBar(widget: widget),
+                if (widget.viewModel.search.running)
+                  const Expanded(
+                    child: Center(child: CircularProgressIndicator()),
+                  ),
+                if (widget.viewModel.search.error)
+                  Expanded(
+                    child: Center(
+                      child: ErrorIndicator(
+                        title: AppLocalization.of(
+                          context,
+                        ).errorWhileLoadingDestinations,
+                        label: AppLocalization.of(context).tryAgain,
+                        onPressed: widget.viewModel.search.execute,
+                      ),
+                    ),
+                  ),
+              ],
+            );
+          },
+          child: ListenableBuilder(
+            listenable: widget.viewModel,
+            builder: (context, child) {
+              return Padding(
+                padding: Dimens.of(context).edgeInsetsScreenHorizontal,
+                child: CustomScrollView(
+                  slivers: [
+                    SliverToBoxAdapter(child: _AppSearchBar(widget: widget)),
+                    _Grid(viewModel: widget.viewModel),
+                  ],
+                ),
+              );
+            },
+          ),
+        ),
+      ),
+    );
+  }
+
+  void _onResult() {
+    if (widget.viewModel.updateItineraryConfig.completed) {
+      widget.viewModel.updateItineraryConfig.clearResult();
+      context.go(Routes.activities);
+    }
+
+    if (widget.viewModel.updateItineraryConfig.error) {
+      widget.viewModel.updateItineraryConfig.clearResult();
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text(AppLocalization.of(context).errorWhileSavingItinerary),
+        ),
+      );
+    }
+  }
+}
+
+class _AppSearchBar extends StatelessWidget {
+  const _AppSearchBar({required this.widget});
+
+  final ResultsScreen widget;
+
+  @override
+  Widget build(BuildContext context) {
+    return SafeArea(
+      top: true,
+      bottom: false,
+      child: Padding(
+        padding: EdgeInsets.only(
+          top: Dimens.of(context).paddingScreenVertical,
+          bottom: Dimens.mobile.paddingScreenVertical,
+        ),
+        child: AppSearchBar(
+          config: widget.viewModel.config,
+          onTap: () {
+            // Navigate to SearchFormScreen and edit search
+            context.pop();
+          },
+        ),
+      ),
+    );
+  }
+}
+
+class _Grid extends StatelessWidget {
+  const _Grid({required this.viewModel});
+
+  final ResultsViewModel viewModel;
+
+  @override
+  Widget build(BuildContext context) {
+    return SliverGrid(
+      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
+        crossAxisCount: 2,
+        crossAxisSpacing: 8.0,
+        mainAxisSpacing: 8.0,
+        childAspectRatio: 182 / 222,
+      ),
+      delegate: SliverChildBuilderDelegate((context, index) {
+        final destination = viewModel.destinations[index];
+        return ResultCard(
+          key: ValueKey(destination.ref),
+          destination: destination,
+          onTap: () {
+            viewModel.updateItineraryConfig.execute(destination.ref);
+          },
+        );
+      }, childCount: viewModel.destinations.length),
+    );
+  }
+}