Flutter 搜索栏插件未显示,TabBar处于颤振状态
对于我的颤振项目,我添加了Flutter 搜索栏插件未显示,TabBar处于颤振状态,flutter,searchbar,Flutter,Searchbar,对于我的颤振项目,我添加了loader\u search\u bar插件,还添加了Tabbar。这是我的代码 Widget build(BuildContext context) { return MaterialApp( home: DefaultTabController( length: 3, child: Scaffold( appBar:SearchBar( defaultBar:
loader\u search\u bar
插件,还添加了Tabbar
。这是我的代码
Widget build(BuildContext context) {
return MaterialApp(
home: DefaultTabController(
length: 3,
child: Scaffold(
appBar:SearchBar(
defaultBar: AppBar(
leading: IconButton(
icon: Icon(Icons.menu),
onPressed: null,
),
bottom: TabBar(
tabs: [
Tab(icon: Icon(Icons.directions_car)),
Tab(icon: Icon(Icons.directions_transit)),
Tab(icon: Icon(Icons.directions_bike)),
],
),
title: Text('Default app bar title'),
),
// onQueryChanged: (query) => _handleQueryChanged(context, query),
onQuerySubmitted: (query){print(query);},
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
],
),
),
),
),
);
}
小部件构建(构建上下文){
返回材料PP(
主页:DefaultTabController(
长度:3,
孩子:脚手架(
应用栏:搜索栏(
defaultBar:AppBar(
领先:IconButton(
图标:图标(图标菜单),
onPressed:null,
),
底部:选项卡栏(
选项卡:[
选项卡(图标:图标(图标方向车)),
选项卡(图标:图标(图标方向和交通)),
选项卡(图标:图标(图标方向)),
],
),
标题:文本(“默认应用程序栏标题”),
),
//onQueryChanged:(查询)=>\u handleQueryChanged(上下文,查询),
onQuerySubmitted:(查询){print(查询);},
),
正文:中(
子:列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
正文(
“您已经按了这么多次按钮:”,
),
],
),
),
),
),
);
}
这就是结果。
正如您在屏幕截图中看到的,搜索栏未显示。如何解决此问题?使用PreferredSize包裹效果很好。您可以在下面看到完整的代码
代码片段
DefaultTabController(
length: 3,
child: Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(100.0),
child: SearchBar(
defaultBar: AppBar(
完整代码
import 'package:flutter/material.dart';
import 'package:loader_search_bar/loader_search_bar.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return DefaultTabController(
length: 3,
child: Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(100.0),
child: SearchBar(
defaultBar: AppBar(
leading: IconButton(
icon: Icon(Icons.menu),
onPressed: null,
),
bottom: TabBar(
tabs: [
Tab(icon: Icon(Icons.directions_car)),
Tab(icon: Icon(Icons.directions_transit)),
Tab(icon: Icon(Icons.directions_bike)),
],
),
title: Text('Default app bar title'),
),
// onQueryChanged: (query) => _handleQueryChanged(context, query),
onQuerySubmitted: (query) {
print(query);
},
),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
],
),
),
),
);
}
}
导入“包装:颤振/材料.省道”;
导入“package:loader_search_bar/loader_search_bar.dart”;
void main()=>runApp(MyApp());
类MyApp扩展了无状态小部件{
//此小部件是应用程序的根。
@凌驾
小部件构建(构建上下文){
返回材料PP(
标题:“颤振演示”,
主题:主题数据(
//这是应用程序的主题。
//
//尝试使用“flutter run”运行应用程序。您将看到
//应用程序有一个蓝色工具栏。然后,在不退出应用程序的情况下,重试
//将下面的primarySwatch更改为Colors.green,然后调用
//“热重新加载”(在运行“颤振运行”的控制台中按“r”,
//或者只需将更改保存到颤振IDE中的“热重新加载”。
//请注意,计数器没有重置回零;应用程序
//未重新启动。
主样本:颜色。蓝色,
),
主页:MyHomePage(标题:“颤振演示主页”),
);
}
}
类MyHomePage扩展StatefulWidget{
MyHomePage({Key,this.title}):超级(Key:Key);
//此小部件是应用程序的主页。它是有状态的,表示
//它有一个状态对象(定义如下),其中包含影响
//看起来怎么样。
//此类是状态的配置。它保存值(在此
//案例名称)由家长(在本例中为应用程序小部件)提供,以及
//由State的build方法使用。小部件子类中的字段包括
//始终标记为“最终”。
最后的字符串标题;
@凌驾
_MyHomePageState createState()=>\u MyHomePageState();
}
类_MyHomePageState扩展状态{
int _计数器=0;
void _incrementCounter(){
设置状态(){
//这个对setState的调用告诉颤振框架,某些东西
//已在此状态下更改,这将导致它重新运行下面的生成方法
//以便显示能够反映更新的值。如果我们更改
//_计数器,而不调用setState(),则生成方法将不可用
//再打一次电话,似乎什么也没发生。
_计数器++;
});
}
@凌驾
小部件构建(构建上下文){
//每次调用setState时都会重新运行此方法,例如,按done
//通过上面的_incrementCounter方法。
//
//对颤振框架进行了优化,以制定重新运行的构建方法
//快速,这样你就可以重建任何需要更新的东西
//而不是必须单独更改小部件的实例。
返回DefaultTabController(
长度:3,
孩子:脚手架(
appBar:首选大小(
首选尺寸:尺寸。从高度(100.0),
孩子:搜索栏(
defaultBar:AppBar(
领先:IconButton(
图标:图标(图标菜单),
onPressed:null,
),
底部:选项卡栏(
选项卡:[
选项卡(图标:图标(图标方向车)),
选项卡(图标:图标(图标方向和交通)),
选项卡(图标:图标(图标方向)),
],
),
标题:文本(“默认应用程序栏标题”),
),
//onQueryChanged:(查询)=>\u handleQueryChanged(上下文,查询),
onQuerySubmitted:(查询){
打印(查询);
},
),
),
正文:中(
子:列(
mainAxisAlignment:mainAxisAlignment.center,
儿童:[
正文(
“您已经按了这么多次按钮:”,
),
],
),
),
),
);
}
}