如何在无状态小部件上传递flutter中的数据

Question

我正在努力完成学校作业，在将数据传递到无状态小部件时遇到了困难。我有以下课程：

class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Page1(),
);
}
}


class Page1 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: ElevatedButton(
onPressed: () {
Navigator.push(
context, MaterialPageRoute(builder: (context) => Page2(messageData: messageData)));
},
child: Text('Request Chat'),
)),
);
}
}


class Page2 extends StatelessWidget {
//Navigation
static Route route(MessageData data) => MaterialPageRoute(
builder: (context) => Page2(
messageData: data,
),
);
const Page2({Key? key, required this.messageData}) : super(key: key);
final MessageData messageData;
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
iconTheme: Theme.of(context).iconTheme,
centerTitle: false,
),
),
},

@immutable
class MessageData {
const MessageData(
{required this.senderName,
required this.message,
required this.messageDate,
required this.dateMessage,
required this.profilePicture});
final String senderName;
final String message;
final DateTime messageDate;
final String dateMessage;
final String profilePicture;
}

上面有我的消息Data，我需要通过。

基本上，我希望能够导航到Page2，但我在Navigator.push()上一直遇到错误。错误详细信息：Type' can't be assigned to the parameter type 'MessageData'.

当Page2((上没有参数时，错误消息：The named parameter 'messageData' is required, but there's no corresponding argument.

Answer 1

必须使用构造函数传递数据。我希望你能从这个链接中得到一个想法。

Answer 2

您可以将参数传递给小部件，就像传递给Flutter的小部件一样：

///Creating Page2 instances
Page2(text: 'text');
Page2.otherConstructor('text');
///This is how you pass values to widgets
class Page2 extends StatelessWidget {
//Pass `this.field` to the constructor so that you are asking for the field you created.
const Page2({Key? key, required this.text}) : super(key: key);
const Page2.otherConstructor(this.text);
final String text;
@override
Widget build(BuildContext context) {
return Scaffold(
body: Text(text),
);
}
}

如果是State中的StatefulWidget，则可以使用widget.field访问值。