flutter/examples/api/lib/widgets/transitions/relative_positioned_transition.0.dart
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---------

Co-authored-by: Kate Lovett <katelovett@google.com>
Co-authored-by: LongCatIsLooong <31859944+LongCatIsLooong@users.noreply.github.com>
2024-12-19 20:06:21 +00:00

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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 [RelativePositionedTransition].
void main() => runApp(const RelativePositionedTransitionExampleApp());
class RelativePositionedTransitionExampleApp extends StatelessWidget {
const RelativePositionedTransitionExampleApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(home: RelativePositionedTransitionExample());
}
}
class RelativePositionedTransitionExample extends StatefulWidget {
const RelativePositionedTransitionExample({super.key});
@override
State<RelativePositionedTransitionExample> createState() =>
_RelativePositionedTransitionExampleState();
}
/// [AnimationController]s can be created with `vsync: this` because of
/// [TickerProviderStateMixin].
class _RelativePositionedTransitionExampleState extends State<RelativePositionedTransitionExample>
with TickerProviderStateMixin {
late final AnimationController _controller = AnimationController(
duration: const Duration(seconds: 2),
vsync: this,
)..repeat(reverse: true);
@override
void dispose() {
_controller.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
const double smallLogo = 100;
const double bigLogo = 200;
return LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
final Size biggest = constraints.biggest;
return Stack(
children: <Widget>[
RelativePositionedTransition(
size: biggest,
rect: RectTween(
begin: const Rect.fromLTWH(0, 0, bigLogo, bigLogo),
end: Rect.fromLTWH(
biggest.width - smallLogo,
biggest.height - smallLogo,
smallLogo,
smallLogo,
),
).animate(CurvedAnimation(parent: _controller, curve: Curves.elasticInOut)),
child: const Padding(padding: EdgeInsets.all(8), child: FlutterLogo()),
),
],
);
},
);
}
}