size_transition.0.dart 1.54 KB
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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.

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// Flutter code sample for [SizeTransition].
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import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
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  const MyApp({super.key});
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  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
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  const MyStatefulWidget({super.key});
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  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

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/// [AnimationController]s can be created with `vsync: this` because of
/// [TickerProviderStateMixin].
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class _MyStatefulWidgetState extends State<MyStatefulWidget>
    with TickerProviderStateMixin {
  late final AnimationController _controller = AnimationController(
    duration: const Duration(seconds: 3),
    vsync: this,
  )..repeat();
  late final Animation<double> _animation = CurvedAnimation(
    parent: _controller,
    curve: Curves.fastOutSlowIn,
  );

  @override
  void dispose() {
    _controller.dispose();
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    super.dispose();
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  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SizeTransition(
        sizeFactor: _animation,
        axis: Axis.horizontal,
        axisAlignment: -1,
        child: const Center(
          child: FlutterLogo(size: 200.0),
        ),
      ),
    );
  }
}