해설 강의에서는 chartData 위젯이 사용되는데 제 화면에서는 위젯이 안뜹니다. ㅠ

import 'package:flutter/material.dart';


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


class MyApp extends StatelessWidget {
  const MyApp({super.key});


  @override
  Widget build(BuildContext context) {
    const chartData = {
      'korea': [
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
      ],
      'global': [
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
      ],
      'newyork': [
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
        {
          'imageUrl': 'https://i.ibb.co/xf2HpfG/dynamite.jpg',
          'name': 'Dynamite',
          'artist': 'BTS',
        },
      ],
    };
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: Colors.white,
      ),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}


class MyWidget extends StatelessWidget {
  const MyWidget({super.key});


  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Column(
        children: [
          Text(
            '차트',
            style: TextStyle(
              fontWeight: FontWeight.bold,
              fontSize: 18,
              color: Colors.black,
            ),
          ),
          SizedBox(height: 16),
          Expanded(
            child: ListView(
              children: [
                Stack(
                  alignment: Alignment.center,
                  children: [
                    Container(
                      width: double.infinity,
                      height: 180,
                      color: Colors.purple[900],
                    ),
                    Column(
                      children: [
                        Container(
                          width: MediaQuery.of(context).size.width * 0.8,
                          child: ElevatedButton(
                            onPressed: () {},
                            style: ButtonStyle(
                              backgroundColor:
                                  MaterialStateProperty.all(Colors.white),
                            ),
                            child: Text(
                              '국가 및 도시별 차트',
                              style: TextStyle(
                                color: Colors.purple[900],
                                fontWeight: FontWeight.bold,
                              ),
                            ),
                          ),
                        ),
                        SizedBox(
                          height: 8,
                        ),
                        Text("전 세계"),
                      ],
                    ),
                  ],
                ),
                Container(
                  width: double.infinity,
                  height: 8,
                  color: Colors.grey[400],
                ),
                Row(
                  children: [
                    Text(
                      '대한민국 차트',
                      style: TextStyle(
                        fontSize: 16,
                        color: Colors.black,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                    Spacer(),
                    Text(
                      '모두 보기',
                      style: TextStyle(
                        fontSize: 16,
                        color: Colors.blue,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ],
                ),
                Row(
                  children: [chartdata],
                )
              ],
            ),
          )
        ],
      ),
    );
  }
}