前言
Flutter是谷歌的移動UI框架,可以快速在iOS和Android上構建高質量的原生使用者介面。
IT界著名的尼古拉斯·高爾包曾說:輪子是IT進步的階梯!熱門的框架千篇一律,好用輪子萬里挑一!Flutter作為這兩年開始崛起的跨平臺開發框架,其第三方生態相比其他成熟框架還略有不足,但輪子的數量也已經很多了。本系列文章挑選日常app開發常用的輪子分享出來,給大家提高搬磚效率,同時也希望flutter的生態越來越完善,輪子越來越多。
本系列文章準備了超過50個輪子推薦,工作原因,儘量每1-2天出一篇文章。
tip:本系列文章合適已有部分flutter基礎的開發者,入門請戳:flutter官網
正文
輪子
- 輪子名稱:sticky_headers
- 輪子概述:flutter給滾動內容新增粘性header元件.
- 輪子作者:fluttercommunity.dev(官方)
- 推薦指數:★★★★
- 常用指數:★★★★
- 效果預覽: 如原圖載入失敗,點選檢視原圖
安裝
dependencies:
sticky_headers: ^0.1.8+1
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import 'package:sticky_headers/sticky_headers.dart';
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使用方法
在列表項中,使用StickyHeader(),基本用法:(gif效果圖中的預設效果)
ListView.builder(
itemCount: 12,
itemBuilder: (context, index) {
return StickyHeader(
header: Container( //header元件
height: 50.0,
color: Colors.blueGrey[700],
padding: EdgeInsets.symmetric(horizontal: 16.0),
alignment: Alignment.centerLeft,
child: Text('Header #$index',
style: const TextStyle(color: Colors.white),
),
),
content: Container(//內容元件
child: Image.network(imgs[index], fit: BoxFit.cover,width: double.infinity, height: 200.0),
),
);
}
)
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在列表項中,使用StickyHeaderBuilder()來自定義更多的header效果和事件:(gif效果圖中的自定義header效果)
ListView.builder(
itemCount: 12,
itemBuilder: (context, index) {
return StickyHeaderBuilder(
builder: (BuildContext context, double stuckAmount) {
stuckAmount = 1.0 - stuckAmount.clamp(0.0, 1.0);
return new Container(
height: 50.0,
color: Color.lerp(Colors.blue[700], Colors.red[700], stuckAmount),
padding: new EdgeInsets.symmetric(horizontal: 16.0),
alignment: Alignment.centerLeft,
child: new Row(
children: <Widget>[
new Expanded(
child: new Text('Header #$index',
style: const TextStyle(color: Colors.white),
),
),
new Offstage(
offstage: stuckAmount <= 0.0,
child: new Opacity(
opacity: stuckAmount,
child: new IconButton(
icon: new Icon(Icons.favorite, color: Colors.white),
onPressed: () =>
Scaffold.of(context).showSnackBar(
new SnackBar(content: new Text('Favorite #$index'))
),
),
),
),
],
),
);
},
content: new Container(
child: new Image.network(imgs[index], fit: BoxFit.cover,
width: double.infinity, height: 200.0),
),
);
}
)
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在列表項中,使用StickyHeaderBuilder(),overlapHeaders=true,使header懸浮在內容上:(gif效果圖中的header浮動)
ListView.builder(
itemCount: 12,
itemBuilder: (context, index) {
return new StickyHeaderBuilder(
overlapHeaders: true,
builder: (BuildContext context, double stuckAmount) {
stuckAmount = 1.0 - stuckAmount.clamp(0.0, 1.0);
return new Container(
height: 50.0,
color: Colors.grey[900].withOpacity(0.6 + stuckAmount * 0.4),
padding: new EdgeInsets.symmetric(horizontal: 16.0),
alignment: Alignment.centerLeft,
child: new Text('Header #$index',
style: const TextStyle(color: Colors.white),
),
);
},
content: new Container(
child: new Image.network(imgs[index], fit: BoxFit.cover,
width: double.infinity, height: 200.0),
),
);
}
)
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資料分組,在content中渲染子列表,形成類似RN的SectionList:(gif效果圖中的SectionList效果)
class StickyHeadersDemo4 extends StatefulWidget {
StickyHeadersDemo4({Key key}) : super(key: key);
@override
_demoState createState() => _demoState();
}
class _demoState extends State<StickyHeadersDemo4> {
List data=[{
"latter":"A",
"group":[
"A分組1","A分組1","A分組1","A分組1","A分組1","A分組1"
]
},{
"latter":"B",
"group":[
"B分組1","B分組1","B分組1","B分組1","B分組1","B分組1"
]
},{
"latter":"C",
"group":[
"C分組1","C分組1","C分組1","C分組1","C分組1","C分組1"
]
},{
"latter":"D",
"group":[
"D分組1","D分組1","D分組1","D分組1","D分組1","D分組1"
]
},{
"latter":"E",
"group":[
"E分組1","E分組1","E分組1","E分組1","E分組1","E分組1"
]
}];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("sticky_headers"),
actions: <Widget>[
GoWeb(pluginName: 'sticky_headers')
],
),
body: ListView.builder(
itemCount: data.length,
itemBuilder: (context, index) {
return StickyHeader(
header: Container(
height: 50.0,
color: Colors.blueGrey[700],
padding: EdgeInsets.symmetric(horizontal: 16.0),
alignment: Alignment.centerLeft,
child: Text(data[index]['latter'],
style: const TextStyle(color: Colors.white),
),
),
content: Column(
children: buildGroup(data[index]['group']),
),
);
}
)
);
}
List<Widget> buildGroup(List group){
return group.map((item){
return Container(
height: 60,
alignment: Alignment.centerLeft,
padding: EdgeInsets.only(left: 20),
child: Text(item),
);
}).toList();
}
}
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結尾
- 輪子倉庫地址:pub.flutter-io.cn/packages/st…
- 系列演示demo原始碼:github.com/826327700/f…