[英]How to dynamically generate widgets in Flutter?
我有一个虚拟的数据列表。 我希望列表中的每个项目在被点击时显示不同的小部件,类似于联系人应用程序。 在 onPressed 方法中定义小部件总是返回相同的小部件。 如何在不手动创建每个小部件的情况下生成每个小部件?
void az() {
int c = "A".codeUnitAt(0);
int end = "Z".codeUnitAt(0);
while (c <= end) {
items.add(FlatButton.icon(
icon: Icon(Icons.image_aspect_ratio),
label: Text(
String.fromCharCode(c),
style: TextStyle(fontSize: 20),
),
onPressed: (){
print(String.fromCharCode(c)); //This should return a different widget
},
));
c++;
}
}
您可以在下面复制粘贴运行完整代码
您start
在for
循环中声明一个局部变量
代码片段
void az() {
int c = "A".codeUnitAt(0);
int end = "Z".codeUnitAt(0);
for (int start = c; start <= end; start++) {
items.add(FlatButton.icon(
icon: Icon(Icons.image_aspect_ratio),
label: Text(
String.fromCharCode(start),
style: TextStyle(fontSize: 20),
),
onPressed: () {
print(String.fromCharCode(
start)); //This should return a different widget
},
));
}
}
output
I/flutter (12880): A
I/flutter (12880): B
I/flutter (12880): C
工作演示
完整代码
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;
List<Widget> items = [];
void az() {
int c = "A".codeUnitAt(0);
int end = "Z".codeUnitAt(0);
for (int start = c; start <= end; start++) {
items.add(FlatButton.icon(
icon: Icon(Icons.image_aspect_ratio),
label: Text(
String.fromCharCode(start),
style: TextStyle(fontSize: 20),
),
onPressed: () {
print(String.fromCharCode(
start)); //This should return a different widget
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
SecondRoute(yourParameter: String.fromCharCode(start))));
},
));
}
}
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
void initState() {
// TODO: implement initState
super.initState();
WidgetsBinding.instance.addPostFrameCallback((_) {
az();
setState(() {});
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: items,
),
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
class SecondRoute extends StatelessWidget {
final String yourParameter;
const SecondRoute({Key key, this.yourParameter}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('$yourParameter'),
),
body: Center(
child: RaisedButton(
onPressed: () {
Navigator.pop(context);
},
child: Text('Go back!'),
),
),
);
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.