flutter/examples/api/lib/widgets/basic/indexed_stack.0.dart
LongCatIsLooong 30fe6e7857
Wire up the system text scaler from PlatformDispatcher (#159999)
The equality of 2 `SystemTextScaler` is determined by the platform's
`textScaleFactor` scalar, because the `scale` method is always
monotonically increasing wrt `textScaleFactor`.
On Android the scalar reflects the user configuration in system
preference it seems:
https://developer.android.com/reference/android/content/res/Configuration#fontScale

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [ ] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
2025-05-13 23:52:05 +00:00

132 lines
3.7 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 [IndexedStack].
void main() => runApp(const IndexedStackApp());
class IndexedStackApp extends StatelessWidget {
const IndexedStackApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: const Text('IndexedStack Sample')),
body: const IndexedStackExample(),
),
);
}
}
class IndexedStackExample extends StatefulWidget {
const IndexedStackExample({super.key});
@override
State<IndexedStackExample> createState() => _IndexedStackExampleState();
}
class _IndexedStackExampleState extends State<IndexedStackExample> {
List<String> names = <String>['Dash', 'John', 'Mary'];
int index = 0;
final TextEditingController fieldText = TextEditingController();
@override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
SizedBox(
width: 300,
child: TextField(
decoration: const InputDecoration(
border: OutlineInputBorder(),
hintText: 'Enter the name for a person to track',
),
onSubmitted: (String value) {
setState(() {
names.add(value);
});
fieldText.clear();
},
controller: fieldText,
),
),
const SizedBox(height: 50),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
GestureDetector(
onTap: () {
setState(() {
index = (index - 1) % names.length;
});
},
child: const Icon(Icons.chevron_left, key: Key('gesture1')),
),
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
IndexedStack(
index: index,
children: <Widget>[for (final String name in names) PersonTracker(name: name)],
),
],
),
GestureDetector(
onTap: () {
setState(() {
index = (index + 1) % names.length;
});
},
child: const Icon(Icons.chevron_right, key: Key('gesture2')),
),
],
),
],
);
}
}
class PersonTracker extends StatefulWidget {
const PersonTracker({super.key, required this.name});
final String name;
@override
State<PersonTracker> createState() => _PersonTrackerState();
}
class _PersonTrackerState extends State<PersonTracker> {
int counter = 0;
@override
Widget build(BuildContext context) {
return Container(
key: Key(widget.name),
decoration: BoxDecoration(
color: const Color.fromARGB(255, 239, 248, 255),
border: Border.all(color: const Color.fromARGB(255, 54, 60, 244)),
borderRadius: const BorderRadius.all(Radius.circular(10)),
),
padding: const EdgeInsets.all(16.0),
child: Column(
children: <Widget>[
Text('Name: ${widget.name}'),
Text('Score: $counter'),
TextButton.icon(
key: Key('increment${widget.name}'),
icon: const Icon(Icons.add),
onPressed: () {
setState(() {
counter += 1;
});
},
label: const Text('Increment'),
),
],
),
);
}
}