forked from lxm_flutter/FlutterUnit
89 lines
2.9 KiB
Dart
89 lines
2.9 KiB
Dart
import 'package:flutter/material.dart';
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/// create by 张风捷特烈 on 2020/9/21
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/// contact me by email 1981462002@qq.com
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/// 说明: 350 BoxScrollView 盒滑动视图
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/// BoxScrollView 类是一个继承自 ScrollView 的抽象类，所以无法直接使用，它的子类有 ListView、GridView。一般不自己实现子类使用它。
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/// link 183,162,163
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///
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// {
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// "widgetId": 350,
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// "name": 'BoxScrollView 介绍',
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// "priority": 1,
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// "subtitle":
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// "【reverse】 : 是否反向 【bool】\n"
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// "【scrollDirection】 : 滑动方向 【Axis】\n"
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// "【cacheExtent】 : 缓存长 【double】\n"
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// "【dragStartBehavior】 : 拖动行为 【DragStartBehavior】\n"
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// "【clipBehavior】 : 裁剪行为 【ClipBehavior】\n"
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// "【controller】 : 控制器 【ScrollController】",
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// }
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class BoxScrollViewDemo extends StatelessWidget {
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const BoxScrollViewDemo({Key? key}) : super(key: key);
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final String info =
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'BoxScrollView 是 ScrollView 的子类，实现了它的抽象方法，且暴露出另一个抽象方法 buildChildLayout，返回 Sliver 家族 Widget，'
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'其子类有 ListView 和 GridView，分别使用 Sliver 家族相关List、Gird列表组件实现的。';
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@override
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Widget build(BuildContext context) {
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return SizedBox(
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height: 300,
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child: Column(
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children: [
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Container(
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color: Colors.blue.withOpacity(0.1),
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padding: const EdgeInsets.all(10),
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margin: const EdgeInsets.all(10),
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child: Text(info),
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),
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Expanded(child: MyBoxScrollView()),
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],
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),
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);
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}
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}
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class MyBoxScrollView extends BoxScrollView {
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MyBoxScrollView({Key? key}) : super(key: key);
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final List<Color> data = [
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Colors.purple[50]!,
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Colors.purple[100]!,
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Colors.purple[200]!,
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Colors.purple[300]!,
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Colors.purple[400]!,
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Colors.purple[500]!,
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Colors.purple[600]!,
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Colors.purple[700]!,
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Colors.purple[800]!,
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Colors.purple[900]!,
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];
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String colorString(Color color) =>
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"#${color.value.toRadixString(16).padLeft(8, '0').toUpperCase()}";
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@override
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Widget buildChildLayout(BuildContext context)=> SliverFixedExtentList(
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itemExtent: 60,
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delegate: SliverChildBuilderDelegate(
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(_, int index) => Container(
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alignment: Alignment.center,
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width: 100,
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height: 50,
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color: data[index],
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child: Text(
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colorString(data[index]),
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style: const TextStyle(color: Colors.white, shadows: [
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Shadow(
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color: Colors.black,
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offset: Offset(.5, .5),
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blurRadius: 2)
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]),
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),
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),
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childCount: data.length),
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);
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}
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