forked from lxm_flutter/FlutterUnit
118 lines
3.3 KiB
Dart
118 lines
3.3 KiB
Dart
import 'package:flutter/material.dart';
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/// create by 张风捷特烈 on 2020/8/14
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/// contact me by email 1981462002@qq.com
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/// 说明: PageStorage 210 0 页面存储器 可以将页面状态进行存储,在切页时可以保持状态。源码中在ScrollView、PageView、ExpansionTile等皆有应用。
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// {
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// "widgetId": 210,
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// "name": "PageStorage基本使用",
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// "priority": 1,
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// "subtitle": "【bucket】 : 存储区 【PageStorageBucket】\n"
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// "【child】: 子组件 【Widget】\n"
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// "上面切换界面初始化组件时并不会将状态重置。如上CountWidget，子组件需要在初始化时从存储器中读取状态，在改变状态时将状态量写入存储器。另外，如果使用MaterialApp已经内置了PageStorage,不过你也可以创建PageStorage。",
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// }
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class PageStorageDemo extends StatefulWidget {
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const PageStorageDemo({Key? key}) : super(key: key);
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@override
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_PageStorageDemoState createState() => _PageStorageDemoState();
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}
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class _PageStorageDemoState extends State<PageStorageDemo> {
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int _pageIndex = 0;
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final PageStorageBucket _bucket = PageStorageBucket();
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@override
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Widget build(BuildContext context) {
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return SizedBox(
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height: 200,
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child: Scaffold(
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body: PageStorage(
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child: _buildContentByIndex(),
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bucket: _bucket,
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),
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bottomNavigationBar: BottomNavigationBar(
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elevation: 0,
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backgroundColor: Colors.blueAccent.withAlpha(55),
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currentIndex: _pageIndex,
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onTap: (int index) {
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setState(() {
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_pageIndex = index;
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});
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},
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items: const [
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BottomNavigationBarItem(
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icon: Icon(Icons.home),
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label: 'Home',
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),
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BottomNavigationBarItem(
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icon: Icon(Icons.settings),
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label: 'Setting',
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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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Widget _buildContentByIndex() {
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if (_pageIndex == 0) {
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return const CountWidget(key: PageStorageKey('CountWidget1'));
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}
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if (_pageIndex == 1) {
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return const CountWidget(key: PageStorageKey('CountWidget2'));
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}
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return ListView();
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}
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}
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class CountWidget extends StatefulWidget {
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const CountWidget({Key? key}) : super(key: key);
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@override
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_CountWidgetState createState() => _CountWidgetState();
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}
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class _CountWidgetState extends State<CountWidget> {
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int _count = 0;
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@override
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void initState() {
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super.initState();
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_count = PageStorage.of(context)?.readState(context);
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}
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@override
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Widget build(BuildContext context) {
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return Container(
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alignment: Alignment.center,
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child: Column(
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mainAxisSize: MainAxisSize.min,
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children: [
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Text('点击了$_count次'),
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MaterialButton(
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onPressed: _addCount,
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child: const Icon(
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Icons.add,
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color: Colors.white,
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),
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color: Colors.green,
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shape: const CircleBorder(
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side: BorderSide(width: 2.0, color: Color(0xFFDFDFDF)),
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))
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],
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),
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);
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}
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void _addCount() {
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setState(() {
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_count++;
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PageStorage.of(context)?.writeState(context, _count);
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});
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}
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}
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