mirror of https://github.com/flutter/samples.git
109 lines
2.8 KiB
109 lines
2.8 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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import 'package:flutter/foundation.dart';
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import 'package:flutter/widgets.dart';
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class CarouselDemo extends StatelessWidget {
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static String routeName = '/misc/carousel';
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static const List<String> fileNames = [
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'assets/eat_cape_town_sm.jpg',
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'assets/eat_new_orleans_sm.jpg',
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'assets/eat_sydney_sm.jpg',
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];
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final List<Widget> images =
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fileNames.map((file) => Image.asset(file, fit: BoxFit.cover)).toList();
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@override
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Widget build(context) {
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return Scaffold(
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appBar: AppBar(
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title: const Text('Carousel Demo'),
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),
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body: Center(
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child: Padding(
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padding: const EdgeInsets.all(16),
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child: AspectRatio(
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aspectRatio: 1,
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child: Carousel(itemBuilder: widgetBuilder),
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),
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),
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),
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);
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}
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Widget widgetBuilder(BuildContext context, int index) {
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return images[index % images.length];
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}
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}
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typedef OnCurrentItemChangedCallback = void Function(int currentItem);
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class Carousel extends StatefulWidget {
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final IndexedWidgetBuilder itemBuilder;
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const Carousel({Key? key, required this.itemBuilder}) : super(key: key);
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@override
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_CarouselState createState() => _CarouselState();
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}
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class _CarouselState extends State<Carousel> {
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late final PageController _controller;
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late int _currentPage;
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bool _pageHasChanged = false;
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@override
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void initState() {
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super.initState();
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_currentPage = 0;
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_controller = PageController(
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viewportFraction: .85,
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initialPage: _currentPage,
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);
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}
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@override
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Widget build(context) {
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var size = MediaQuery.of(context).size;
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return PageView.builder(
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onPageChanged: (value) {
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setState(() {
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_pageHasChanged = true;
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_currentPage = value;
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});
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},
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controller: _controller,
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itemBuilder: (context, index) => AnimatedBuilder(
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animation: _controller,
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builder: (context, child) {
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var result = _pageHasChanged ? _controller.page! : _currentPage * 1.0;
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// The horizontal position of the page between a 1 and 0
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var value = result - index;
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value = (1 - (value.abs() * .5)).clamp(0.0, 1.0);
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return Center(
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child: SizedBox(
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height: Curves.easeOut.transform(value) * size.height,
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width: Curves.easeOut.transform(value) * size.width,
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child: child,
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),
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);
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},
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child: widget.itemBuilder(context, index),
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),
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);
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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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}
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