您应该在构造函数中输入参数，并在Widget本身中定义它们，如下所示

你的问题存在是因为你传递给CardWidgets的构造函数的值实际上并没有被保存在任何地方，所以当CardWid方法被调用时，参数（类型为dynamic）为null。

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

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

class HomePage extends StatelessWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const Scaffold(body:CardWidget(
      pcolor: Colors.orangeAccent,
      ptext: 'I need team for First Person Shooter',
      paccount: 'gamedev21',
      pdate: 'February 12, 2023, 21:00',
      peoplein: 2,
    ),);
  }
}

class CardWidget extends StatelessWidget {
  const CardWidget({
    Key? key,
    required this.pcolor,
    required this.ptext,
    required this.paccount,
    required this.pdate,
    required this.peoplein,
  }) : super(key: key);

  final Color pcolor;
  final String ptext;
  final String paccount;
  final String pdate;
  final int peoplein;

  Widget cardWidget() {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 15, vertical: 5),
      color: pcolor,
      child: Column(
        children: [
          Text("$ptext, $paccount, $pdate, $peoplein"),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return cardWidget();
  }
}

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

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