| // 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. |
| |
| // Template: dev/snippets/config/templates/stateful_widget_scaffold_center_freeform_state.tmpl |
| // |
| // Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring |
| // of samples, and may be ignored if you are just exploring the sample. |
| |
| // Flutter code sample for SliverFadeTransition |
| // |
| //*************************************************************************** |
| //* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| // Creates a [CustomScrollView] with a [SliverFixedExtentList] that uses a |
| // [SliverFadeTransition] to fade the list in and out. |
| |
| //* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //*************************************************************************** |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| /// This is the main application widget. |
| class MyApp extends StatelessWidget { |
| const MyApp({Key? key}) : super(key: key); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return MaterialApp( |
| title: _title, |
| home: Scaffold( |
| appBar: AppBar(title: const Text(_title)), |
| body: const Center( |
| child: MyStatefulWidget(), |
| ), |
| ), |
| ); |
| } |
| } |
| |
| /// This is the stateful widget that the main application instantiates. |
| class MyStatefulWidget extends StatefulWidget { |
| const MyStatefulWidget({Key? key}) : super(key: key); |
| |
| @override |
| State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); |
| } |
| |
| /// This is the private State class that goes with MyStatefulWidget. |
| //******************************************************************** |
| //* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| class _MyStatefulWidgetState extends State<MyStatefulWidget> |
| with SingleTickerProviderStateMixin { |
| late final AnimationController controller = AnimationController( |
| duration: const Duration(milliseconds: 1000), |
| vsync: this, |
| ); |
| late final Animation<double> animation = CurvedAnimation( |
| parent: controller, |
| curve: Curves.easeIn, |
| ); |
| |
| @override |
| void initState() { |
| super.initState(); |
| animation.addStatusListener((AnimationStatus status) { |
| if (status == AnimationStatus.completed) { |
| controller.reverse(); |
| } else if (status == AnimationStatus.dismissed) { |
| controller.forward(); |
| } |
| }); |
| controller.forward(); |
| } |
| |
| @override |
| Widget build(BuildContext context) { |
| return CustomScrollView(slivers: <Widget>[ |
| SliverFadeTransition( |
| opacity: animation, |
| sliver: SliverFixedExtentList( |
| itemExtent: 100.0, |
| delegate: SliverChildBuilderDelegate( |
| (BuildContext context, int index) { |
| return Container( |
| color: index.isEven ? Colors.indigo[200] : Colors.orange[200], |
| ); |
| }, |
| childCount: 5, |
| ), |
| ), |
| ) |
| ]); |
| } |
| } |
| |
| //* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //******************************************************************** |