如何解决问题的孩子没有在抽屉颤振中定义

Question

class Drawer extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Drawer(
child: ListView(
padding: EdgeInsets.zero,
children: [
UserAccountsDrawerHeader(
accountName: Text("Anus"),
accountEmail: Text("[e-mail]"),
currentAccountPicture: CircleAvatar(
backgroundImage: NetworkImage(
"https://images.unsplash.com/photo-1533227268428-f9ed0900fb3b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1158&q=80"),
),
),
ListTile(
leading: Icon(Icons.person),
title: Text("Account"),
subtitle: Text("Personal"),
trailing: Icon(Icons.edit),
),
ListTile(
leading: Icon(Icons.email),
title: Text("Email"),
subtitle: Text("[e-mail]"),
trailing: Icon(Icons.send),
),
],
),
);
}
}

如何解决颤振中的此问题

我想创建抽屉，但当我试图在抽屉的新文件中创建抽屉时，命名参数"child"没有定义

Answer 1

您在小部件的定义中使用了相同的小部件
这是一个工作代码

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> {
@override
void initState() {
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: _buildBody(),
floatingActionButton: FloatingActionButton(
onPressed: () {},
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
Widget _buildBody() {
return Drawer();
}
}
class Drawer extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ListView(
padding: EdgeInsets.zero,
children: [
UserAccountsDrawerHeader(
accountName: Text("Anus"),
accountEmail: Text("[e-mail]"),
currentAccountPicture: CircleAvatar(
backgroundImage: NetworkImage(
"https://images.unsplash.com/photo-1533227268428-f9ed0900fb3b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1158&q=80"),
),
),
ListTile(
leading: Icon(Icons.person),
title: Text("Account"),
subtitle: Text("Personal"),
trailing: Icon(Icons.edit),
),
ListTile(
leading: Icon(Icons.email),
title: Text("Email"),
subtitle: Text("[e-mail]"),
trailing: Icon(Icons.send),
),
],
);
}
}

Answer 2

您的问题源于您为类(您的自定义小部件(使用了名称抽屉，这意味着编译器不知道要使用哪个抽屉小部件，无论是材料库中的抽屉还是您刚刚定义的抽屉。

要解决此问题，只需将类的名称更改为AppDrawer或任何其他名称，编译器就会开始识别您正在尝试使用材料库中定义的Drawer。