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johnpryan/main.dart Secret

Last active Oct 20, 2020
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TransitionDelegate example
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;
}
}
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