mirror of
https://github.com/flutter/flutter.git
synced 2025-06-03 00:51:18 +00:00
fd9ce27748
This does a cleanup of the examples, removing all of the "section" markers and extra comments that we don't need anymore now that the samples are no longer in the source code. It also removes the --template arguments from the {@tool dartpad} and {@tool sample} directives, since those are no longer used. It converts two examples that I discovered were still embedded into linked examples in the examples folder.
I didn't delete the templates from the snippets config folder yet, because there are still embedded samples in the dart:ui package from the engine that use them. Once dart:ui no longer uses the templates, they can be removed.
I bumped the version of the snippets package to pick up a change that allows removal of the --template argument.
98 lines
2.9 KiB
Dart
98 lines
2.9 KiB
Dart
// Copyright 2014 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.
|
|
|
|
// Flutter code sample for RestorationMixin
|
|
|
|
import 'package:flutter/material.dart';
|
|
|
|
void main() => runApp(const RestorationExampleApp());
|
|
|
|
class RestorationExampleApp extends StatelessWidget {
|
|
const RestorationExampleApp({Key? key}) : super(key: key);
|
|
|
|
@override
|
|
Widget build(BuildContext context) {
|
|
return const MaterialApp(
|
|
restorationScopeId: 'app',
|
|
title: 'Restorable Counter',
|
|
home: RestorableCounter(restorationId: 'counter'),
|
|
);
|
|
}
|
|
}
|
|
|
|
class RestorableCounter extends StatefulWidget {
|
|
const RestorableCounter({Key? key, this.restorationId}) : super(key: key);
|
|
|
|
final String? restorationId;
|
|
|
|
@override
|
|
State<RestorableCounter> createState() => _RestorableCounterState();
|
|
}
|
|
|
|
// The [State] object uses the [RestorationMixin] to make the current value
|
|
// of the counter restorable.
|
|
class _RestorableCounterState extends State<RestorableCounter>
|
|
with RestorationMixin {
|
|
// The current value of the counter is stored in a [RestorableProperty].
|
|
// During state restoration it is automatically restored to its old value.
|
|
// If no restoration data is available to restore the counter from, it is
|
|
// initialized to the specified default value of zero.
|
|
final RestorableInt _counter = RestorableInt(0);
|
|
|
|
// In this example, the restoration ID for the mixin is passed in through
|
|
// the [StatefulWidget]'s constructor.
|
|
@override
|
|
String? get restorationId => widget.restorationId;
|
|
|
|
@override
|
|
void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
|
|
// All restorable properties must be registered with the mixin. After
|
|
// registration, the counter either has its old value restored or is
|
|
// initialized to its default value.
|
|
registerForRestoration(_counter, 'count');
|
|
}
|
|
|
|
void _incrementCounter() {
|
|
setState(() {
|
|
// The current value of the property can be accessed and modified via
|
|
// the value getter and setter.
|
|
_counter.value++;
|
|
});
|
|
}
|
|
|
|
@override
|
|
void dispose() {
|
|
_counter.dispose();
|
|
super.dispose();
|
|
}
|
|
|
|
@override
|
|
Widget build(BuildContext context) {
|
|
return Scaffold(
|
|
appBar: AppBar(
|
|
title: const Text('Restorable Counter'),
|
|
),
|
|
body: Center(
|
|
child: Column(
|
|
mainAxisAlignment: MainAxisAlignment.center,
|
|
children: <Widget>[
|
|
const Text(
|
|
'You have pushed the button this many times:',
|
|
),
|
|
Text(
|
|
'${_counter.value}',
|
|
style: Theme.of(context).textTheme.headline4,
|
|
),
|
|
],
|
|
),
|
|
),
|
|
floatingActionButton: FloatingActionButton(
|
|
onPressed: _incrementCounter,
|
|
tooltip: 'Increment',
|
|
child: const Icon(Icons.add),
|
|
),
|
|
);
|
|
}
|
|
}
|