Membuat tambahan widget di akhir sebuah list of widgets

widget.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  State<MyApp> createState() => _MyAppState();
}

List<Map<String, dynamic>> cards = [
  {
    'name': 'BRI',
    'amount': 2500,
  },
  {
    'name': 'BNI',
    'amount': 3000,
  },
];

class _MyAppState extends State<MyApp> {
  Widget plus() {
    return GestureDetector(
      onTap: () {
        cards.add({
          'name': 'Tambah',
          'amount': 2000,
        });
        setState(() {});
      },
      child: Container(
        height: 50,
        width: 100,
        child: Center(
          child: Icon(Icons.plus_one),
        ),
      ),
    );
  }

  List<Widget> cardWidgets() {
    List<Widget> widgets = List<Widget>.generate(
      cards.length,
      (index) => Container(
        height: 50,
        width: 200,
        child: Column(
          children: [
            Text('Name: ${cards[index]['name']}'),
            Text('Amount: ${cards[index]['amount']}'),
          ],
        ),
        decoration: BoxDecoration(
          color: Colors.blueGrey,
          borderRadius: BorderRadius.circular(10),
        ),
      ),
    );

    widgets.add(plus());

    return widgets;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: Container(
            height: 200,
            width: double.infinity,
            child: ListView(
              scrollDirection: Axis.horizontal,
              children: cardWidgets(),
            ),
          ),
        ),
      ),
    );
  }
}