[英]Creating a Custom widget in Flutter
import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
int _weight =60;
class RoundIconData extends StatefulWidget {
@override
_RoundIconDataState createState() => _RoundIconDataState();
}
class _RoundIconDataState extends State<RoundIconData> {
RoundIconData({@required this.icon,@required this.pressme});
final IconData icon;
final int pressme;
@override
Widget build(BuildContext context) {
return RawMaterialButton(
child: Icon(icon),
onPressed: (){
setState(() {
if(icon == FontAwesomeIcons.minus){
_weight--;
}
else{
_weight++
}
});
},
elevation: 6.0,
constraints: BoxConstraints.tightFor(
width: 56.0,
height: 56.0,
),
shape: CircleBorder(),
fillColor: Color(0xFF4C4F5E),
);
}
}
我在創建這個時遇到錯誤。
我想要的是
帶有 RawmaterialButton 的自定義小部件,我可以通過它添加圖標。 如果我添加 icon.minus 那么我給定的私有權重要減少,否則給定私有權重要增加
您可以在下面復制粘貼運行完整代碼
您必須將以下代碼移動到RoundIconData
RoundIconData({@required this.icon,@required this.pressme});
final IconData icon;
final int pressme;
並通過回調進行刷新
工作演示
完整代碼
import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.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(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
int weight = 60;
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;
refresh() {
setState(() {});
}
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
RoundIconData(
icon: Icon(FontAwesomeIcons.minus),
notifyParent: refresh,
),
RoundIconData(
icon: Icon(Icons.add),
notifyParent: refresh,
),
Text(
'${weight}',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
class RoundIconData extends StatefulWidget {
final Icon icon;
final int pressme;
final Function() notifyParent;
RoundIconData(
{@required this.icon,
@required this.pressme,
@required this.notifyParent});
@override
_RoundIconDataState createState() => _RoundIconDataState();
}
class _RoundIconDataState extends State<RoundIconData> {
@override
Widget build(BuildContext context) {
return RawMaterialButton(
child: widget.icon,
onPressed: () {
print(widget.icon.toString());
print(Icon(FontAwesomeIcons.minus).toString());
if (widget.icon.toString() == Icon(FontAwesomeIcons.minus).toString()) {
weight--;
widget.notifyParent();
print(weight);
} else {
weight++;
widget.notifyParent();
print(weight);
}
},
elevation: 6.0,
constraints: BoxConstraints.tightFor(
width: 56.0,
height: 56.0,
),
shape: CircleBorder(),
fillColor: Color(0xFF4C4F5E),
);
}
}
通過組合較小的小部件(而不是擴展它們)來構建自定義小部件。 它有點類似於在 Android 中實現自定義ViewGroup
,其中所有構建塊都已經存在,但您提供不同的行為 - 例如,自定義布局邏輯。
構建一個在構造函數中帶有標簽的 CustomButton? 創建一個CustomButton
,它組合一個帶有標簽的ElevatedButton
,而不是通過擴展ElevatedButton
:
class CustomButton extends StatelessWidget {
final String label;
CustomButton(this.label);
@override
Widget build(BuildContext context) {
return ElevatedButton(onPressed: () {}, child: Text(label));
}
}
然后使用CustomButton
,就像使用任何其他 Flutter 小部件一樣:
@override
Widget build(BuildContext context) {
return Center(
child: CustomButton("Hello"),
);
}
在 Flutter 中創建自定義小部件
import 'package:flutter/material.dart';
class WelcomePage extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Auth',
theme: ThemeData(
primaryColor: Colors.purple,
scaffoldBackgroundColor: Colors.white,
),
home:Scaffold(
body: Center(
child: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
"WELCOME TO XYZ",
style: TextStyle(fontWeight: FontWeight.bold,color: Colors.purple,fontSize: 25),
),
Padding(
padding: const EdgeInsets.only(right: 40),
child: Image.asset(
"assets/images/food_order.png",
height: 200,
),
),
SizedBox(height: 10 ),
loginMethod(),
signUpMethod(),
],
),
),
),
),
);
}
// Login Button Method Widget
Widget loginMethod(){
return Container(
margin: EdgeInsets.symmetric(vertical: 10),
width: 200,
height: 50,
child: ClipRRect(
borderRadius: BorderRadius.circular(29),
child: FlatButton(
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 40),
color: Colors.blue,
onPressed: (){},
child: Text(
'Login',
style: TextStyle(color: Colors.white),
),
),
),
);
}
// Signup button method widget
Widget signUpMethod (){
return Container(
margin: EdgeInsets.symmetric(vertical: 10),
width: 200,
height: 50,
child: ClipRRect(
borderRadius: BorderRadius.circular(29),
child: FlatButton(
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 40),
color: Colors.blue,
onPressed: (){},
child: Text(
'Sign up',
style: TextStyle(color: Colors.white),
),
),
),
);
}
}
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