尝试将字符串传递给Flutter中的无状态小部件

Question

当我尝试使用传递给无状态小部件的字符串时出现错误。在内部版本中打印的消息会打印我正在发送的消息，但是当我尝试在Text（message）中使用它时，会得到以下提示：

Arguments of a constant creation must be constant expressions. Try making the argument a valid constant, or use 'new' to call the constructor.

import 'package:flutter/material.dart';

class ProgressCenter extends StatelessWidget {
  const ProgressCenter({
    Key key,
    this.message,
  }) : super(key: key);

  final String message;

  @override
  Widget build(BuildContext context) {
    print(message);
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: <Widget>[
          SizedBox(
            child: CircularProgressIndicator(),
            width: 60,
            height: 60,
          ),
          const Padding(
            padding: EdgeInsets.only(top: 16),
            child: Text(message),
          )
        ],
      ),
    );
  }
}