forked from lxm_flutter/FlutterUnit
70 lines
2.5 KiB
Dart
70 lines
2.5 KiB
Dart
import 'package:flutter/gestures.dart';
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import 'package:flutter/material.dart';
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import 'package:flutter/rendering.dart';
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/// create by 张风捷特烈 on 2020/8/2
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/// contact me by email 1981462002@qq.com
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/// 说明: 253 Scrollable 可滑动组件 实现了一个可滚动组件的交互模型,需要viewportBuilder进的viewport的构造。是ScrollView的核心实现组件之一，一般不直接使用。
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// {
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// "widgetId": 253,
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// "name": "Scrollable的基本使用",
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// "priority": 1,
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// "subtitle": "【viewportBuilder】 : 视口构造器 【ViewportBuilder】\n"
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// "【axisDirection】: 滑动方向 【AxisDirection】\n"
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// "【controller】: 滑动控制器 【ScrollController】\n"
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// "【dragStartBehavior】: t拖动行为 【DragStartBehavior】\n"
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// "【physics】: 滚动现象 【ScrollPhysics】\n",
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// }
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class ScrollableDemo extends StatelessWidget {
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ScrollableDemo({Key? key}) : super(key: key);
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final List<Color> data = List.generate(32, (i) => Color(0xFF6600FF - 2 * i));
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@override
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Widget build(BuildContext context) {
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return SizedBox(
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height: 250,
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child: Scrollable(
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axisDirection: AxisDirection.down,
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physics: const BouncingScrollPhysics(),
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dragStartBehavior: DragStartBehavior.start,
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viewportBuilder: (ctx, position) => Viewport(
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cacheExtent: 200,
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cacheExtentStyle: CacheExtentStyle.pixel,
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offset: position,
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slivers: <Widget>[_buildSliverList()],
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),
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),
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);
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}
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Widget _buildSliverList() => SliverList(
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delegate: SliverChildBuilderDelegate(
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(_, int index) => Container(
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margin: const EdgeInsets.only(top: 1),
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alignment: Alignment.center,
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width: 100,
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height: 60,
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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(
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color: Colors.white,
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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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),
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childCount: data.length),
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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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}
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