mirror of https://github.com/flutter/samples.git
75 lines
2.0 KiB
75 lines
2.0 KiB
// Copyright 2019 The Flutter team. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:flutter/material.dart';
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class TweenDemo extends StatefulWidget {
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const TweenDemo({super.key});
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static const String routeName = '/basics/tweens';
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@override
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State<TweenDemo> createState() => _TweenDemoState();
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}
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class _TweenDemoState extends State<TweenDemo>
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with SingleTickerProviderStateMixin {
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static const Duration _duration = Duration(seconds: 1);
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static const double accountBalance = 1000000;
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late final AnimationController controller;
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late final Animation<double> animation;
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@override
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void initState() {
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super.initState();
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controller = AnimationController(vsync: this, duration: _duration)
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..addListener(() {
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// Marks the widget tree as dirty
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setState(() {});
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});
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animation = Tween(begin: 0.0, end: accountBalance).animate(controller);
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}
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@override
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void dispose() {
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controller.dispose();
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super.dispose();
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}
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@override
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Widget build(BuildContext context) {
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return Scaffold(
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appBar: AppBar(
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title: const Text('Tweens'),
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),
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body: Center(
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child: Column(
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mainAxisSize: MainAxisSize.min,
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children: [
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ConstrainedBox(
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constraints: const BoxConstraints(maxWidth: 200),
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child: Text('\$${animation.value.toStringAsFixed(2)}',
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style: const TextStyle(fontSize: 24)),
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),
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ElevatedButton(
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child: Text(
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controller.status == AnimationStatus.completed
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? 'Buy a Mansion'
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: 'Win Lottery',
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),
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onPressed: () {
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if (controller.status == AnimationStatus.completed) {
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controller.reverse();
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} else {
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controller.forward();
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}
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},
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)
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],
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),
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),
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);
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}
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}
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