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// 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 [InheritedModel].
import 'package:flutter/material.dart';
enum LogoAspect { backgroundColor, large }
void main() => runApp(const InheritedModelApp());
class InheritedModelApp extends StatelessWidget {
const InheritedModelApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
home: InheritedModelExample(),
);
}
}
class LogoModel extends InheritedModel<LogoAspect> {
const LogoModel({
super.key,
this.backgroundColor,
this.large,
required super.child,
});
final Color? backgroundColor;
final bool? large;
static Color? backgroundColorOf(BuildContext context) {
return InheritedModel.inheritFrom<LogoModel>(context, aspect: LogoAspect.backgroundColor)?.backgroundColor;
}
static bool sizeOf(BuildContext context) {
return InheritedModel.inheritFrom<LogoModel>(context, aspect: LogoAspect.large)?.large ?? false;
}
@override
bool updateShouldNotify(LogoModel oldWidget) {
return backgroundColor != oldWidget.backgroundColor ||
large != oldWidget.large;
}
@override
bool updateShouldNotifyDependent(LogoModel oldWidget, Set<LogoAspect> dependencies) {
if (backgroundColor != oldWidget.backgroundColor && dependencies.contains(LogoAspect.backgroundColor)) {
return true;
}
if (large != oldWidget.large && dependencies.contains(LogoAspect.large)) {
return true;
}
return false;
}
}
class InheritedModelExample extends StatefulWidget {
const InheritedModelExample({super.key});
@override
State<InheritedModelExample> createState() => _InheritedModelExampleState();
}
class _InheritedModelExampleState extends State<InheritedModelExample> {
bool large = false;
Color color = Colors.blue;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('InheritedModel Sample')),
body: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Center(
child: LogoModel(
backgroundColor: color,
large: large,
child: const BackgroundWidget(
child: LogoWidget(),
),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
ElevatedButton(
onPressed: () {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('Rebuilt Background'),
duration: Duration(milliseconds: 500),
),
);
setState(() {
if (color == Colors.blue){
color = Colors.red;
} else {
color = Colors.blue;
}
});
},
child: const Text('Update background'),
),
ElevatedButton(
onPressed: () {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('Rebuilt LogoWidget'),
duration: Duration(milliseconds: 500),
),
);
setState(() {
large = !large;
});
},
child: const Text('Resize Logo'),
),
],
)
],
),
);
}
}
class BackgroundWidget extends StatelessWidget {
const BackgroundWidget({super.key, required this.child});
final Widget child;
@override
Widget build(BuildContext context) {
final Color color = LogoModel.backgroundColorOf(context)!;
return AnimatedContainer(
padding: const EdgeInsets.all(12.0),
color: color,
duration: const Duration(seconds: 2),
curve: Curves.fastOutSlowIn,
child: child,
);
}
}
class LogoWidget extends StatelessWidget {
const LogoWidget({super.key});
@override
Widget build(BuildContext context) {
final bool largeLogo = LogoModel.sizeOf(context);
return AnimatedContainer(
padding: const EdgeInsets.all(20.0),
duration: const Duration(seconds: 2),
curve: Curves.fastLinearToSlowEaseIn,
alignment: Alignment.center,
child: FlutterLogo(size: largeLogo ? 200.0 : 100.0),
);
}
}