forked from lxm_flutter/FlutterUnit
124 lines
3.5 KiB
Dart
124 lines
3.5 KiB
Dart
|
||
import 'package:flutter/cupertino.dart';
|
||
import 'package:flutter/material.dart';
|
||
import 'package:flutter/rendering.dart';
|
||
|
||
|
||
/// create by 张风捷特烈 on 2020/9/21
|
||
/// contact me by email 1981462002@qq.com
|
||
/// 说明: 304 SliverLayoutBuilder Sliver布局构造器 Sliver家族一员，在滑动过程中可以通过回调出的 SliverConstraints 对象进行子组件的构造。
|
||
// {
|
||
// "widgetId": 304,
|
||
// "name": 'SliverLayoutBuilder基本使用',
|
||
// "priority": 1,
|
||
// "subtitle":
|
||
// "【builder】 : 组件构造器 【SliverLayoutWidgetBuilder】",
|
||
// }
|
||
class SliverLayoutBuilderDemo extends StatefulWidget {
|
||
@override
|
||
_SliverLayoutBuilderDemoState createState() =>
|
||
_SliverLayoutBuilderDemoState();
|
||
}
|
||
|
||
class _SliverLayoutBuilderDemoState extends State<SliverLayoutBuilderDemo> {
|
||
final data = <Color>[
|
||
Colors.orange[50],
|
||
Colors.orange[100],
|
||
Colors.orange[200],
|
||
Colors.orange[300],
|
||
Colors.orange[400],
|
||
Colors.orange[500],
|
||
Colors.orange[600],
|
||
Colors.orange[700],
|
||
Colors.orange[800],
|
||
Colors.orange[900],
|
||
];
|
||
|
||
@override
|
||
Widget build(BuildContext context) {
|
||
return Container(
|
||
height: 300,
|
||
child: CustomScrollView(
|
||
physics: BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
|
||
slivers: <Widget>[
|
||
_buildSliverAppBar(),
|
||
SliverLayoutBuilder(
|
||
builder: _buildSliver,
|
||
),
|
||
_buildSliverList(),
|
||
],
|
||
),
|
||
);
|
||
}
|
||
|
||
Widget _buildSliverList() => SliverFixedExtentList(
|
||
itemExtent: 50,
|
||
delegate: SliverChildBuilderDelegate(
|
||
(_, int index) => Container(
|
||
alignment: Alignment.center,
|
||
width: 100,
|
||
height: 60,
|
||
color: data[index],
|
||
child: Text(
|
||
colorString(data[index]),
|
||
style: TextStyle(color: Colors.white, shadows: [
|
||
Shadow(
|
||
color: Colors.black,
|
||
offset: Offset(.5, .5),
|
||
blurRadius: 2)
|
||
]),
|
||
),
|
||
),
|
||
childCount: data.length),
|
||
);
|
||
|
||
Widget _buildSliverAppBar() {
|
||
return SliverAppBar(
|
||
expandedHeight: 120.0,
|
||
leading: Container(
|
||
margin: EdgeInsets.all(10),
|
||
child: Image.asset('assets/images/icon_head.webp')),
|
||
title: Text('张风捷特烈'),
|
||
actions: _buildActions(),
|
||
elevation: 5,
|
||
pinned: true,
|
||
backgroundColor: Colors.orange,
|
||
flexibleSpace: FlexibleSpaceBar(
|
||
titlePadding: EdgeInsets.only(left: 55, bottom: 15), //标题边距
|
||
collapseMode: CollapseMode.parallax, //视差效果
|
||
background: Image.asset(
|
||
"assets/images/caver.webp",
|
||
fit: BoxFit.cover,
|
||
),
|
||
),
|
||
);
|
||
}
|
||
|
||
List<Widget> _buildActions() => <Widget>[
|
||
IconButton(
|
||
onPressed: () {},
|
||
icon: Icon(
|
||
Icons.star_border,
|
||
color: Colors.white,
|
||
),
|
||
)
|
||
];
|
||
|
||
String colorString(Color color) =>
|
||
"#${color.value.toRadixString(16).padLeft(8, '0').toUpperCase()}";
|
||
|
||
Widget _buildSliver(BuildContext context, SliverConstraints constraints) {
|
||
return SliverToBoxAdapter(
|
||
child: Container(
|
||
alignment: Alignment.center,
|
||
height: constraints.remainingPaintExtent / 3,
|
||
color: Colors.red,
|
||
child: Text(
|
||
"SliverLayoutBuilder",
|
||
style: TextStyle(color: Colors.white, fontSize: 20),
|
||
),
|
||
),
|
||
);
|
||
}
|
||
}
|