我的代码中有一个问题，ElevatedButton（）onPressed中的函数addCu（）：当父Column（）是AlertDialog（）的子级时，属性不向ListVew.Builder（）添加项
代码如下：

import 'package:flutter/material.dart';
import '../constants.dart';
import '../models/currencies.dart';

class AddCurrency extends StatefulWidget {
  final Function addCu;

  const AddCurrency({
    super.key,
    required this.addCu,
  });

  @override
  State<AddCurrency> createState() => _AddCurrencyState();
}

class _AddCurrencyState extends State<AddCurrency> {

  @override
  Widget build(BuildContext context) {

    void addNewCurrency(String cuName, double cuPrice, double cuPercentage) {

      final newCu = Currencies(
        currencyName: cuName,
        currencyPrice: cuPrice,
        currencyPercent: cuPercentage,

      );

      setState(() {
        currenciesList.add(newCu);
      });

    }

    return FloatingActionButton(
      backgroundColor: Colors.pink,
      child: const Icon(Icons.notification_add),
      onPressed: () => showDialog(context: context, builder: (context) => AlertDialog(
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            TextFormFieldSource(
              data: 'Add Currency Name',
              controller: currencyNameController,
            ),
            SizedBox(
              height: kDefaultPadding,
            ),
            TextFormFieldSource(
              data: 'Add Currency Price',
              controller: currencyPriceController,
            ),
            SizedBox(
              height: kDefaultPadding,
            ),
            TextFormFieldSource(
              data: 'Add Currency Percentage',
              controller: currencyPercentController,
            ),
            SizedBox(
              height: kDefaultPadding,
            ),
            ElevatedButton(
              onPressed: () {
                widget.addCu(
                  currencyNameController.text,
                  double.parse(currencyPriceController.text),
                  double.parse(currencyPercentController.text),
                );
                addNewCurrency;
                Navigator.of(context).pop();
              },
              child: const Text('Add currency now!'),
            ),
          ],
        ),
      ),),
    );
  }
}

请注意，该函数在删除FloatingActionButton（）、showDialog（）和AlertDialog（）时工作并添加项。
在下面的代码中，为什么我们需要在ListVew.Builder（）中使用一个空列表“listOfCurrencies”，而不是我们想要向其中添加项目的列表“currenciesList”，后者位于包含模型的dart文件中，并且其中至少有一个对象示例？

import 'package:flutter/material.dart';

import '../constants.dart';
import '../models/currencies.dart';

class CurrencyList extends StatelessWidget {

  final List<Currencies> listOfCurrencies;

  const CurrencyList({Key? key, required this.listOfCurrencies}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      height: 300,
      child: ListView.builder(
        shrinkWrap: true,
        itemCount: listOfCurrencies.length,
        itemBuilder: (context , index) => Card(
          color: Colors.white,
          child: Row(
            children: [
              Container(
                margin: const EdgeInsets.all(15),
                height: 50,
                width: 50,
                decoration: const BoxDecoration(
                    color: Colors.purple,
                    shape: BoxShape.circle,
                    boxShadow: [
                      BoxShadow(
                        offset: Offset(0, 5),
                        blurRadius: 15,
                      ),
                    ]),
                child: Center(
                  child: Text(
                    listOfCurrencies[index].currencyName!.substring(0, 1).toUpperCase(),
                    style: const TextStyle(
                      fontSize: 30,
                      fontWeight: FontWeight.bold,
                      color: Colors.white,
                    ),
                  ),
                ),
              ),

              SizedBox(
                width: kDefaultPadding,
              ),

              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    listOfCurrencies[index].currencyName!,

                    style: const TextStyle(
                      fontSize: 20,
                      fontWeight: FontWeight.bold,

                    ),
                  ),
                  SizedBox(
                    width: kDefaultPadding,
                  ),

                   Text(
                    '\$${listOfCurrencies[index].currencyPrice!}',
                  ),
                  SizedBox(
                    width: kDefaultPadding,
                  ),

                  Text(
                    '1 hour: ${listOfCurrencies[index].currencyPercent!}%',
                    style: const TextStyle(
                      color: Colors.red,
                    ),
                  ),
                ],
              )
            ],
          ),
        ),
      ),
    );
  }
}

当需要Maven的时候，他们去了哪里？！！！！