flutter SliverAppBar+tabbar+tabbarview使用

1.使用效果

2.初始化tabs

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@override
void initState() {
// TODO: implement initState
super.initState();
_tabs = [
Tab(
icon: Icon(Icons.map),
text: "Tab1",
),
Tab(
icon: Icon(Icons.camera_alt),
text: "Tab2",
),
];
}

3.组件一定要是NestedScrollView，可以展示sleverAppBar

背景SliverAppBar

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///背景图和title展示
SliverAppBar(
pinned: true, //title固定在顶部不会滑动出屏幕
expandedHeight: 200,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text("TabViewTwo"),
background: Image.asset(
"assets/images/a.jpg",
fit: BoxFit.cover,
),
),
),

tabbar展示

首先创建_SliverAppBarDelegate继承SliverPersistentHeaderDelegate，融合tabbar

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class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
final TabBar tabBar;

_SliverAppBarDelegate(this.tabBar);

@override
Widget build(
BuildContext context, double shrinkOffset, bool overlapsContent) {
// TODO: implement build
return Container(
child: tabBar,
);
}

@override
// TODO: implement maxExtent
double get maxExtent => tabBar.preferredSize.height;

@override
// TODO: implement minExtent
double get minExtent => tabBar.preferredSize.height;

@override
bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) {
// TODO: implement shouldRebuild
return false;
}
}

展示

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///tabbar展示
SliverPersistentHeader(
delegate: _SliverAppBarDelegate(
TabBar(
tabs: _tabs,
isScrollable: false,
indicatorSize: TabBarIndicatorSize.label,
labelColor: Colors.black87,
unselectedLabelColor: Colors.grey,
),
),
pinned: true,
)

完整代码

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import 'package:flutter/material.dart';

///带有slever
class TabViewTwo extends StatefulWidget {
@override
_TabViewTwoState createState() => _TabViewTwoState();
}

class _TabViewTwoState extends State<TabViewTwo> {
List<Tab> _tabs = [];

@override
void initState() {
// TODO: implement initState
super.initState();
_tabs = [
Tab(
icon: Icon(Icons.map),
text: "Tab1",
),
Tab(
icon: Icon(Icons.camera_alt),
text: "Tab2",
),
];
}

@override
Widget build(BuildContext context) {
return DefaultTabController(
length: 2,
child: Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return [
///背景图和title展示
SliverAppBar(
pinned: true, //title固定在顶部不会滑动出屏幕
expandedHeight: 200,
flexibleSpace: FlexibleSpaceBar(
centerTitle: true,
title: Text("TabViewTwo"),
background: Image.asset(
"assets/images/a.jpg",
fit: BoxFit.cover,
),
),
),

///tabbar展示
SliverPersistentHeader(
delegate: _SliverAppBarDelegate(
TabBar(
tabs: _tabs,
isScrollable: false,
indicatorSize: TabBarIndicatorSize.label,
labelColor: Colors.black87,
unselectedLabelColor: Colors.grey,
),
),
pinned: true,
)
];
},
body: TabBarView(
children: ["hahhh", "哈哈哈哈"]
.map((value) => Center(
child: Text("$value"),
))
.toList(),
),
),
),
);
}
}

class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
final TabBar tabBar;

_SliverAppBarDelegate(this.tabBar);

@override
Widget build(
BuildContext context, double shrinkOffset, bool overlapsContent) {
// TODO: implement build
return Container(
child: tabBar,
);
}

@override
// TODO: implement maxExtent
double get maxExtent => tabBar.preferredSize.height;

@override
// TODO: implement minExtent
double get minExtent => tabBar.preferredSize.height;

@override
bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) {
// TODO: implement shouldRebuild
return false;
}
}

github地址：https://github.com/korolzhang/flutter_widget.git