Add navigator 2 samples (#606)

* add navigation_and_routing sample * Add navigation samples and README * remove "goals" section * add newlines * add copyright headers * Update README, remove pubspec comments, add description
2025-11-08 13:58:47 +00:00 · 2020-12-11 17:27:01 -08:00
parent 3d943d7d46
commit d73beef792
67 changed files with 2732 additions and 0 deletions
--- a/navigation_and_routing/lib/nav_2_advanced/transition_delegate.dart
+++ b/navigation_and_routing/lib/nav_2_advanced/transition_delegate.dart
@@ -0,0 +1,244 @@
+// Copyright 2020, 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.
+
+/// Shows how a custom TransitionDelegate can be used to customized when
+/// transition animations are shown. (For example, [when two routes are popped
+/// off the stack](https://github.com/flutter/flutter/issues/12146), however the
+/// default TransitionDelegate will handle this if you are using Navigator 2.0)
+import 'package:flutter/material.dart';
+
+void main() {
+  runApp(BooksApp());
+}
+
+class Book {
+  final String title;
+  final String author;
+
+  Book(this.title, this.author);
+}
+
+class BooksApp extends StatefulWidget {
+  @override
+  State<StatefulWidget> createState() => _BooksAppState();
+}
+
+class _BooksAppState extends State<BooksApp> {
+  BookRouterDelegate _routerDelegate = BookRouterDelegate();
+  BookRouteInformationParser _routeInformationParser =
+  BookRouteInformationParser();
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp.router(
+      title: 'Books App',
+      routerDelegate: _routerDelegate,
+      routeInformationParser: _routeInformationParser,
+    );
+  }
+}
+
+class BookRouteInformationParser extends RouteInformationParser<BookRoutePath> {
+  @override
+  Future<BookRoutePath> parseRouteInformation(
+      RouteInformation routeInformation) async {
+    final uri = Uri.parse(routeInformation.location);
+
+    if (uri.pathSegments.length >= 2) {
+      var remaining = uri.pathSegments[1];
+      return BookRoutePath.details(int.tryParse(remaining));
+    } else {
+      return BookRoutePath.home();
+    }
+  }
+
+  @override
+  RouteInformation restoreRouteInformation(BookRoutePath path) {
+    if (path.isHomePage) {
+      return RouteInformation(location: '/');
+    }
+    if (path.isDetailsPage) {
+      return RouteInformation(location: '/book/${path.id}');
+    }
+    return null;
+  }
+}
+
+class BookRouterDelegate extends RouterDelegate<BookRoutePath>
+    with ChangeNotifier, PopNavigatorRouterDelegateMixin<BookRoutePath> {
+  final GlobalKey<NavigatorState> navigatorKey;
+
+  Book _selectedBook;
+
+  List<Book> books = [
+    Book('Stranger in a Strange Land', 'Robert A. Heinlein'),
+    Book('Foundation', 'Isaac Asimov'),
+    Book('Fahrenheit 451', 'Ray Bradbury'),
+  ];
+
+  BookRouterDelegate() : navigatorKey = GlobalKey<NavigatorState>();
+
+  BookRoutePath get currentConfiguration => _selectedBook == null
+      ? BookRoutePath.home()
+      : BookRoutePath.details(books.indexOf(_selectedBook));
+
+  @override
+  Widget build(BuildContext context) {
+    return Navigator(
+      key: navigatorKey,
+      transitionDelegate: NoAnimationTransitionDelegate(),
+      pages: [
+        MaterialPage(
+          key: ValueKey('BooksListPage'),
+          child: BooksListScreen(
+            books: books,
+            onTapped: _handleBookTapped,
+          ),
+        ),
+        if (_selectedBook != null) BookDetailsPage(book: _selectedBook)
+      ],
+      onPopPage: (route, result) {
+        if (!route.didPop(result)) {
+          return false;
+        }
+
+        // Update the list of pages by setting _selectedBook to null
+        _selectedBook = null;
+        notifyListeners();
+
+        return true;
+      },
+    );
+  }
+
+  @override
+  Future<void> setNewRoutePath(BookRoutePath path) async {
+    if (path.isDetailsPage) {
+      _selectedBook = books[path.id];
+    }
+  }
+
+  void _handleBookTapped(Book book) {
+    _selectedBook = book;
+    notifyListeners();
+  }
+}
+
+class BookDetailsPage extends Page {
+  final Book book;
+
+  BookDetailsPage({
+    this.book,
+  }) : super(key: ValueKey(book));
+
+  Route createRoute(BuildContext context) {
+    return MaterialPageRoute(
+      settings: this,
+      builder: (BuildContext context) {
+        return BookDetailsScreen(book: book);
+      },
+    );
+  }
+}
+
+class BookRoutePath {
+  final int id;
+
+  BookRoutePath.home() : id = null;
+
+  BookRoutePath.details(this.id);
+
+  bool get isHomePage => id == null;
+
+  bool get isDetailsPage => id != null;
+}
+
+class BooksListScreen extends StatelessWidget {
+  final List<Book> books;
+  final ValueChanged<Book> onTapped;
+
+  BooksListScreen({
+    @required this.books,
+    @required this.onTapped,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(),
+      body: ListView(
+        children: [
+          for (var book in books)
+            ListTile(
+              title: Text(book.title),
+              subtitle: Text(book.author),
+              onTap: () => onTapped(book),
+            )
+        ],
+      ),
+    );
+  }
+}
+
+class BookDetailsScreen extends StatelessWidget {
+  final Book book;
+
+  BookDetailsScreen({
+    @required this.book,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(),
+      body: Padding(
+        padding: const EdgeInsets.all(8.0),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            if (book != null) ...[
+              Text(book.title, style: Theme.of(context).textTheme.headline6),
+              Text(book.author, style: Theme.of(context).textTheme.subtitle1),
+            ],
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+class NoAnimationTransitionDelegate extends TransitionDelegate<void> {
+  @override
+  Iterable<RouteTransitionRecord> resolve({
+    List<RouteTransitionRecord> newPageRouteHistory,
+    Map<RouteTransitionRecord, RouteTransitionRecord>
+    locationToExitingPageRoute,
+    Map<RouteTransitionRecord, List<RouteTransitionRecord>>
+    pageRouteToPagelessRoutes,
+  }) {
+    final results = <RouteTransitionRecord>[];
+
+    for (final pageRoute in newPageRouteHistory) {
+      if (pageRoute.isWaitingForEnteringDecision) {
+        pageRoute.markForAdd();
+      }
+      results.add(pageRoute);
+    }
+
+    for (final exitingPageRoute in locationToExitingPageRoute.values) {
+      if (exitingPageRoute.isWaitingForExitingDecision) {
+        exitingPageRoute.markForRemove();
+        final pagelessRoutes = pageRouteToPagelessRoutes[exitingPageRoute];
+        if (pagelessRoutes != null) {
+          for (final pagelessRoute in pagelessRoutes) {
+            pagelessRoute.markForRemove();
+          }
+        }
+      }
+
+      results.add(exitingPageRoute);
+    }
+    return results;
+  }
+}