flutter/examples/api/lib/material/switch/switch.2.dart
Nate Wilson 6ff806d74e
Use .fromMap() constructors in example code (#152535)
Currently, there are 21 `.resolveWith()` calls in example files.

This pull request changes 11 of them to use the new `.fromMap()` constructor. (Seven of them are now `const`!)

```dart
ListTile(
  iconColor: WidgetStateColor.fromMap(<WidgetStatesConstraint, Color>{
    WidgetState.disabled: Colors.red,
    WidgetState.selected: Colors.green,
    WidgetState.any:      Colors.black,
  }),
  // The same can be achieved using the .resolveWith() constructor.
  // The text color will be identical to the icon color above.
  textColor: WidgetStateColor.resolveWith((Set<WidgetState> states) {
    if (states.contains(WidgetState.disabled)) {
      return Colors.red;
    }
    if (states.contains(WidgetState.selected)) {
      return Colors.green;
    }
    return Colors.black;
  }),
),
```
2024-08-01 22:28:22 +00:00

72 lines
1.7 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.
import 'package:flutter/material.dart';
/// Flutter code sample for [Switch].
void main() => runApp(const SwitchApp());
class SwitchApp extends StatelessWidget {
const SwitchApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(useMaterial3: true),
home: Scaffold(
appBar: AppBar(title: const Text('Switch Sample')),
body: const Center(
child: SwitchExample(),
),
),
);
}
}
class SwitchExample extends StatefulWidget {
const SwitchExample({super.key});
@override
State<SwitchExample> createState() => _SwitchExampleState();
}
class _SwitchExampleState extends State<SwitchExample> {
bool light0 = true;
bool light1 = true;
static const WidgetStateProperty<Icon> thumbIcon = WidgetStateProperty<Icon>.fromMap(
<WidgetStatesConstraint, Icon>{
WidgetState.selected: Icon(Icons.check),
WidgetState.any: Icon(Icons.close),
},
);
@override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Switch(
value: light0,
onChanged: (bool value) {
setState(() {
light0 = value;
});
},
),
Switch(
thumbIcon: thumbIcon,
value: light1,
onChanged: (bool value) {
setState(() {
light1 = value;
});
},
),
],
);
}
}