[英]sliver app bar with search functionality in flutter
希望你有美好的一天。 我想在下面實現這樣的東西=> gif image 1
誰的 gif 不清楚。它是來自名為Yelp
的應用程序的屏幕截圖。 它是帶有擴展和折疊功能的銀色應用欄。 當它折疊搜索欄固定到標題。 無論如何,到目前為止我已經完成了這個 => gif image 2
當我折疊 sliver 應用欄時,我的搜索欄正在縮小。 我希望當我折疊 sliver 應用欄並修復上面標題中的搜索欄時,搜索不會縮小。 這是我的代碼
import 'package:flutter/material.dart';
class HomePage extends StatefulWidget {
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
double changingHeight;
double appBarHeight;
bool appBarSearchShow = false;
final TextEditingController _filter = new TextEditingController();
List<String> itemList = [];
@override
void initState() {
for (int count = 0; count < 50; count++) {
itemList.add("Item $count");
}
changingHeight = 300;
}
@override
Widget build(BuildContext context) {
appBarHeight = MediaQuery.of(context).padding.top + kToolbarHeight;
return Scaffold(
backgroundColor: Colors.white,
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxScrolled) {
return <Widget>[createSilverAppBar()];
},
body: ListView.builder(
itemCount: itemList.length,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(itemList[index]),
),
);
})),
);
}
SliverAppBar createSilverAppBar() {
return SliverAppBar(
backgroundColor: Colors.white,
expandedHeight: 300,
floating: false,
pinned: true,
// title: appBarSearchShow == true
// ? CupertinoTextField(
// controller: _filter,
// keyboardType: TextInputType.text,
// placeholder: "Search..",
// placeholderStyle: TextStyle(
// color: Color(0xffC4C6CC),
// fontSize: 14.0,
// fontFamily: 'Brutal',
// ),
// prefix: Padding(
// padding: const EdgeInsets.fromLTRB(9.0, 6.0, 9.0, 6.0),
// child: Icon(
// Icons.search,
// ),
// ),
// decoration: BoxDecoration(
// borderRadius: BorderRadius.circular(8.0),
// color: Colors.white,
// ),
// )
// : Container(),
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
if (constraints.biggest.height == appBarHeight) {
appBarSearchShow = true;
} else {
appBarSearchShow = false;
}
return FlexibleSpaceBar(
collapseMode: CollapseMode.parallax,
titlePadding: EdgeInsets.only(bottom: 10),
centerTitle: true,
title: constraints.biggest.height != appBarHeight
? Container(
//margin: EdgeInsets.symmetric(horizontal: 10),
constraints: BoxConstraints(minHeight: 30, maxHeight: 30),
width: 220,
decoration: BoxDecoration(
boxShadow: <BoxShadow>[
BoxShadow(
color: Colors.grey.withOpacity(0.6),
offset: const Offset(1.1, 1.1),
blurRadius: 5.0),
],
),
child: CupertinoTextField(
controller: _filter,
keyboardType: TextInputType.text,
placeholder: 'Search',
placeholderStyle: TextStyle(
color: Color(0xffC4C6CC),
fontSize: 14.0,
fontFamily: 'Brutal',
),
prefix: Padding(
padding: const EdgeInsets.fromLTRB(5.0, 5.0, 0.0, 5.0),
child: Icon(
Icons.search,
size: 18,
),
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8.0),
color: Colors.white,
),
),
)
: Container(),
background: Container(
//height: constraints.maxHeight - 15,
color: Colors.white,
margin: EdgeInsets.only(bottom: 30),
child: Image.asset(
'assets/mainBackImage.jpg',
fit: BoxFit.cover,
),
),
);
}),
);
}
}
任何幫助,將不勝感激。
這是使搜索欄固定並阻止其縮小的解決方案:
您可以使用兩個SilverAppBar
,一個用於背景圖像,一個用於搜索欄。 第一個SilverAppBar
沒有標題和標高,也沒有固定。 第二個SilverAppBar
已固定並具有高度,其標題是SearchBar
。
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxScrolled) {
return <Widget>[
createSilverAppBar1(),
createSilverAppBar2()
];
},
body: ListView.builder(
itemCount: itemList.length,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(itemList[index]),
),
);
})),
);
}
SliverAppBar createSilverAppBar1() {
return SliverAppBar(
backgroundColor: Colors.redAccent,
expandedHeight: 300,
floating: false,
elevation: 0,
flexibleSpace: LayoutBuilder(
builder: (BuildContext context, BoxConstraints constraints) {
return FlexibleSpaceBar(
collapseMode: CollapseMode.parallax,
background: Container(
color: Colors.white,
child: Image.asset(
'assets/mainBackImage.jpg',
fit: BoxFit.cover,
),
),
);
}),
);
}
SliverAppBar createSilverAppBar2() {
return SliverAppBar(
backgroundColor: Colors.redAccent,
pinned: true,
title: Container(
margin: EdgeInsets.symmetric(horizontal: 10),
height: 40,
decoration: BoxDecoration(
boxShadow: <BoxShadow>[
BoxShadow(
color: Colors.grey.withOpacity(0.6),
offset: const Offset(1.1, 1.1),
blurRadius: 5.0),
],
),
child: CupertinoTextField(
controller: _filter,
keyboardType: TextInputType.text,
placeholder: 'Search',
placeholderStyle: TextStyle(
color: Color(0xffC4C6CC),
fontSize: 14.0,
fontFamily: 'Brutal',
),
prefix: Padding(
padding: const EdgeInsets.fromLTRB(5.0, 5.0, 0.0, 5.0),
child: Icon(
Icons.search,
size: 18,
color: Colors.black,
),
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8.0),
color: Colors.white,
),
),
),
);
}
結果:
這是基於gif 圖像 1進行布局的解決方案:
使用Stack
,您可以將搜索欄堆疊在背景之上。 搜索欄的偏移量將是expandedHeight - shrinkOffset - 20
,因為它應該取決於應用欄縮小的程度以及應用欄未縮小時的總高度。 20 是搜索欄高度的一半,減去它以使搜索欄向上移動一半高度。
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxScrolled) {
return <Widget>[
SliverPersistentHeader(
delegate: MySliverAppBar(expandedHeight: 200, filter: _filter),
pinned: true,
),
];
},
body: ListView.builder(
itemCount: itemList.length,
itemBuilder: (context, index) {
return Card(
child: ListTile(
title: Text(itemList[index]),
),
);
})),
);
}
class MySliverAppBar extends SliverPersistentHeaderDelegate {
final double expandedHeight;
final TextEditingController filter;
MySliverAppBar({@required this.expandedHeight, @required this.filter});
@override
Widget build(
BuildContext context, double shrinkOffset, bool overlapsContent) {
var searchBarOffset = expandedHeight - shrinkOffset - 20;
return Stack(
fit: StackFit.expand,
overflow: Overflow.visible,
children: [
Container(
child: Image.network(
'assets/mainBackImage.jpg',
fit: BoxFit.cover,
),
),
(shrinkOffset < expandedHeight - 20) ? Positioned(
top: searchBarOffset,
left: MediaQuery.of(context).size.width / 4,
child: Card(
elevation: 10,
child: SizedBox(
height: 40,
width: MediaQuery.of(context).size.width / 2,
child: CupertinoTextField(
controller: filter,
keyboardType: TextInputType.text,
placeholder: 'Search',
placeholderStyle: TextStyle(
color: Color(0xffC4C6CC),
fontSize: 14.0,
fontFamily: 'Brutal',
),
prefix: Padding(
padding: const EdgeInsets.fromLTRB(5.0, 5.0, 0.0, 5.0),
child: Icon(
Icons.search,
size: 18,
color: Colors.black,
),
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8.0),
color: Colors.white,
),
),
),
),
) : Container(
margin: EdgeInsets.symmetric(
horizontal: MediaQuery.of(context).size.width / 4,
vertical: (kToolbarHeight - 40) / 4
),
child: Card(
elevation: 10,
child: CupertinoTextField(
controller: filter,
keyboardType: TextInputType.text,
placeholder: 'Search',
placeholderStyle: TextStyle(
color: Color(0xffC4C6CC),
fontSize: 14.0,
fontFamily: 'Brutal',
),
prefix: Padding(
padding: const EdgeInsets.fromLTRB(5.0, 5.0, 0.0, 5.0),
child: Icon(
Icons.search,
size: 18,
color: Colors.black,
),
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8.0),
color: Colors.white,
),
),
),
),
],
);
}
@override
double get maxExtent => expandedHeight;
@override
double get minExtent => kToolbarHeight;
@override
bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) => true;
}
結果:
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