[英]How to add decoration DropdownButton in Flutter
我有一個下拉按鈕,如下所示。
child: DropdownButton<String>(
value: dropDownValue,
icon: Icon(Icons.keyboard_arrow_down),
iconSize: 15,
elevation: 16,
style: TextStyle(color: Colors.grey),
underline: Container(
decoration: ShapeDecoration(
shape: RoundedRectangleBorder(
side: BorderSide(width: 1.0, style: BorderStyle.solid),
borderRadius: BorderRadius.all(Radius.circular(5.0)),
),
),
),
onChanged: (String newValue) {
setState(() {
dropDownValue = newValue;
});
},
items: [dropDownValue,...snapshot.data.data]
.map<DropdownMenuItem<String>>((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value.name),
);
}).toList(),
),
我想通過在容器中使用裝飾來像圖像中那樣塑造它,但我無法按照我想要的方式塑造它
但現在這就是我的形象。 如何為下拉按鈕添加邊緣? 有沒有已知的方法?
您可以在下面復制粘貼運行完整代碼
您可以將DropdownButtonFormField
與InputDecoration
設置fillColor
和hintText
使用
代碼片段
DropdownButtonFormField(
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: const BorderRadius.all(
const Radius.circular(30.0),
),
),
filled: true,
hintStyle: TextStyle(color: Colors.grey[800]),
hintText: "Name",
fillColor: Colors.blue[200]),
value: dropDownValue,
工作演示
完整代碼
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
String dropDownValue;
List<String> cityList = [
'Ajman',
'Al Ain',
'Dubai',
'Fujairah',
'Ras Al Khaimah',
'Sharjah',
'Umm Al Quwain'
];
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
void initState() {
//setFilters();
super.initState();
}
setFilters() {
setState(() {
dropDownValue = cityList[2];
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
DropdownButtonFormField(
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: const BorderRadius.all(
const Radius.circular(30.0),
),
),
filled: true,
hintStyle: TextStyle(color: Colors.grey[800]),
hintText: "Name",
fillColor: Colors.blue[200]),
value: dropDownValue,
onChanged: (String Value) {
setState(() {
dropDownValue = Value;
});
},
items: cityList
.map((cityTitle) => DropdownMenuItem(
value: cityTitle, child: Text("$cityTitle")))
.toList(),
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
您可以將DropdownButton
小部件包裝到DecoratedBox
中:
return DecoratedBox(
decoration: ShapeDecoration(
color: Colors.cyan,
shape: RoundedRectangleBorder(
side: BorderSide(width: 1.0, style: BorderStyle.solid, color: Colors.cyan),
borderRadius: BorderRadius.all(Radius.circular(25.0)),
),
),
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 40.0, vertical: 0.0),
child: DropdownButton<String>(
value: dropdownValue,
icon: Icon(null),
elevation: 16,
onChanged: (String newValue) {
setState(() {
dropdownValue = newValue;
});
},
underline: SizedBox(),
items: <String>['City', 'Country', 'State']
.map<DropdownMenuItem<String>>((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}).toList(),
),
),
);
Output:
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