import 'package:flutter/material.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';
const String _kGalleryAssetsPackage = 'flutter_gallery_assets';
class _Page {
_Page({this.label});
final String label;
String get id => label[0];
@override
String toString() => '$runtimeType("$label")';
}
class _CardData {
const _CardData({this.title, this.imageAsset, this.imageAssetPackage});
final String title;
final String imageAsset;
final String imageAssetPackage;
}
final Map<_Page, List<_CardData>> _allPages = <_Page, List<_CardData>>{
new _Page(label: 'LEFT'): <_CardData>[
const _CardData(
title: 'Vintage Bluetooth Radio',
imageAsset: 'shrine/products/radio.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Sunglasses',
imageAsset: 'shrine/products/sunnies.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Clock',
imageAsset: 'shrine/products/clock.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Red popsicle',
imageAsset: 'shrine/products/popsicle.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Folding Chair',
imageAsset: 'shrine/products/lawn_chair.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Green comfort chair',
imageAsset: 'shrine/products/chair.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Old Binoculars',
imageAsset: 'shrine/products/binoculars.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Teapot',
imageAsset: 'shrine/products/teapot.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
const _CardData(
title: 'Blue suede shoes',
imageAsset: 'shrine/products/chucks.png',
imageAssetPackage: _kGalleryAssetsPackage,
),
],
// new _Page(label: 'RIGHT'): <_CardData>[
// const _CardData(
// title: 'Beachball',
// imageAsset: 'shrine/products/beachball.png',
// imageAssetPackage: _kGalleryAssetsPackage,
// ),
// const _CardData(
// title: 'Dipped Brush',
// imageAsset: 'shrine/products/brush.png',
// imageAssetPackage: _kGalleryAssetsPackage,
// ),
// const _CardData(
// title: 'Perfect Goldfish Bowl',
// imageAsset: 'shrine/products/fish_bowl.png',
// imageAssetPackage: _kGalleryAssetsPackage,
// ),
// ],
};
class _CardDataItem extends StatelessWidget {
const _CardDataItem({this.page, this.data});
static const double height = 272.0;
final _Page page;
final _CardData data;
@override
Widget build(BuildContext context) {
return new Card(
child: new Padding(
padding: const EdgeInsets.all(16.0),
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
mainAxisAlignment: MainAxisAlignment.start,
children: [
new Align(
alignment:
page.id == 'L' ? Alignment.centerLeft : Alignment.centerRight,
child: new CircleAvatar(child: new Text('${page.id}')),
),
new SizedBox(
width: 144.0,
height: 144.0,
child: new Image.asset(
data.imageAsset,
package: data.imageAssetPackage,
fit: BoxFit.contain,
),
),
new Center(
child: new Text(
data.title,
style: Theme.of(context).textTheme.title,
),
),
],
),
),
);
}
}
class ScrollViewDemo extends StatefulWidget {
@override
State createState() {
// TODO: implement createState
return ScrollViewDemoState();
}
}
class ScrollViewDemoState extends State {
static const String routeName = '/material/tabs';
ScrollController _controller = new ScrollController();
ScrollController _controller2 = new ScrollController();
double h = 0;
double d15;
double d20;
double d25;
double d30;
double d35;
double d40;
double d45;
double d50;
@override
void initState() {
// TODO: implement initState
super.initState();
_controller.addListener(() {
d15 = ScreenUtil().setWidth(15);
d20 = ScreenUtil().setWidth(20);
d25 = ScreenUtil().setWidth(25);
d30 = ScreenUtil().setWidth(30);
d35 = ScreenUtil().setWidth(35);
d50 = ScreenUtil().setWidth(50);
d40 = ScreenUtil().setWidth(40);
d45 = ScreenUtil().setWidth(45);
double d60 = ScreenUtil().setWidth(60);
double d70 = ScreenUtil().setWidth(70);
double d80 = ScreenUtil().setWidth(80);
double d85 = ScreenUtil().setWidth(85);
double d90 = ScreenUtil().setWidth(90);
double d100 = ScreenUtil().setWidth(100);
setState(() {
if ((_controller.offset > d100)) {
h = d50;
} else if ((_controller.offset > d90)) {
h = d45;
} else if ((_controller.offset > d80)) {
h = d40;
} else if ((_controller.offset > d70)) {
h = d35;
} else if ((_controller.offset > d60)) {
h = d30;
} else if ((_controller.offset > d50)) {
h = d25;
} else if ((_controller.offset > d40)) {
h = d20;
} else if ((_controller.offset > d30)) {
h = d15;
} else {
h = ScreenUtil().setWidth(0);
}
});
});
double start = 0;
_controller2.addListener(() {
// print("---->_controller2:${_controller2.offset}");
if ((_controller2.offset - start).abs() > 3) {
_controller.jumpTo(_controller2.offset);
start = _controller2.offset;
}
});
}
@override
Widget build(BuildContext context) {
return new DefaultTabController(
length: _allPages.length,
child: new Scaffold(
backgroundColor: Colors.white,
body: new NestedScrollView(
controller: _controller,
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return [
new SliverOverlapAbsorber(
handle:
NestedScrollView.sliverOverlapAbsorberHandleFor(context),
child: new SliverAppBar(
actions: [
IconButton(
icon: const Icon(Icons.share),
tooltip: 'Add new entry',
onPressed: () {
/* ... */
},
),
],
leading: Container(
child: Icon(Icons.backspace),
width: 0,
alignment: Alignment.center,
),
title: Text("这是一个标题"),
pinned: true,
//固定在顶部
expandedHeight: ScreenUtil().setWidth(260),
// 这个高度必须比flexibleSpace高度大
forceElevated: innerBoxIsScrolled,
bottom: PreferredSize(
child: new Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(20),
topRight: Radius.circular(20)),
color: Colors.white,
),
height: h,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Container(
child: InkWell(
child: Text(
"导航一",
style: TextStyle(
color:
h > 10 ? Colors.black : Colors.white),
),
onTap: () {
_controller2.animateTo(
ScreenUtil().setWidth(260),
duration: new Duration(seconds: 1),
curve: Curves.ease);
},
),
alignment: Alignment.center,
)
,
InkWell(
child: Text("导航二",
style: TextStyle(
color: h > 10
? Colors.black
: Colors.white)),
onTap: () {
_controller2.animateTo(
ScreenUtil().setWidth(600),
duration: new Duration(seconds: 1),
curve: Curves.ease);
;
})
],
),
),
preferredSize: new Size(double.infinity, h)),
// 46.0为TabBar的高度，也就是tabs.dart中的_kTabHeight值，因为flutter不支持反射所以暂时没法通过代码获取
flexibleSpace: new Container(
child: new Column(
children: [
new Expanded(
child: new Container(
height: ScreenUtil().setWidth(170),
decoration: BoxDecoration(color: Colors.white),
child: Stack(
fit: StackFit.expand,
children: [
Image.asset(
"images/test_1.png",
fit: BoxFit.cover,
height: ScreenUtil().setWidth(150),
),
Stack(
children: [
Container(
height: ScreenUtil().setWidth(30),
width: ScreenUtil().setWidth(375),
decoration: BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(20),
topRight: Radius.circular(20)),
color: Colors.white,
),
child: Container(
margin: EdgeInsets.only(
left: ScreenUtil().setWidth(125)),
child: Row(
children: [
Text(
"这是测试的标题2",
style: TextStyle(
color: Colors.black,
fontSize:
ScreenUtil().setSp(15)),
),
Text(
"描述",
style: TextStyle(
color: Colors.red,
fontSize:
ScreenUtil().setSp(12)),
)
],
),
),
),
Container(
child: Container(
margin: EdgeInsets.only(
left: ScreenUtil().setWidth(10),
right: ScreenUtil().setWidth(10)),
child: Row(
children: [
Image.asset(
"images/test_2.png",
fit: BoxFit.fill,
width:
ScreenUtil().setWidth(116),
height:
ScreenUtil().setWidth(164),
),
Column(
children: [
Text(
"这是测试的标题1",
style: TextStyle(
color: Colors.white),
),
Text(
"副标题1",
style: TextStyle(
color: Colors.red),
),
Text(
"副标题2",
style: TextStyle(
color: Colors.red),
),
Text(
"副标题3",
style: TextStyle(
color: Colors.red),
),
Text(
"副标题4",
style: TextStyle(
color: Colors.red),
)
],
)
],
)),
height: h >= ScreenUtil().setWidth(20)
? (h >= ScreenUtil().setWidth(30)
? (h >= ScreenUtil().setWidth(35)
? (h >= ScreenUtil().setWidth(40)
? 0
: ScreenUtil().setWidth(80))
: ScreenUtil().setWidth(100))
: ScreenUtil().setWidth(140))
: ScreenUtil().setWidth(170),
),
],
alignment: AlignmentDirectional.bottomEnd,
),
],
),
width: double.infinity,
),
)
],
),
),
),
),
];
},
body: new TabBarView(
children: _allPages.keys.map((_Page page) {
return new SafeArea(
top: false,
bottom: false,
child: new Builder(
builder: (BuildContext context) {
return new CustomScrollView(
controller: _controller2,
key: new PageStorageKey<_Page>(page),
slivers: [
new SliverOverlapInjector(
handle:
NestedScrollView.sliverOverlapAbsorberHandleFor(
context),
),
new SliverPadding(
padding: const EdgeInsets.symmetric(
vertical: 8.0,
horizontal: 16.0,
),
sliver: new SliverFixedExtentList(
itemExtent: _CardDataItem.height,
delegate: new SliverChildBuilderDelegate(
(BuildContext context, int index) {
final _CardData data = _allPages[page][index];
return new Padding(
padding: const EdgeInsets.symmetric(
vertical: 8.0,
),
child: new _CardDataItem(
page: page,
data: data,
),
);
},
childCount: _allPages[page].length,
),
),
),
],
);
},
),
);
}).toList(),
),
// body: Column(children: [],),
),
),
);
}
}
说明：
NestedScrollView 与body 中的CustomScrollView滑动冲突解决，通过CustomScrollView的_controller2
控制NestedScrollView的_controller，以达到控制NestedScrollView的滚动的结果，当内部的CustomScrollView滚动时候_controller2监听器里 _controller.jumpTo(_controller2.offset),实现外层的NestedScrollView滚动
