* 겪고 있는 문제 상황을 최대한 자세하게 작성해주세요.

* 문제 해결을 위해 어떤 시도를 해보았는지 구체적으로 함께 알려주세요.

1) 다른 분께서 질문해주신 내용과 동일한데요 ->

아래의 경우 웹뷰 플러터 버전을 3.0.0 으로 바꿔서 해결하긴 했는데, 혹시 버전 4로 하려면 코드를 어떻게 바꿔야 할까요? 구글에서 안나와서 여쭤봅니다.

2) 추가로, 웹뷰 관련 코드를 모두 입력하였는데, 실제로 앱 내에서 웹뷰가 실행되지 않는데요, 혹시 왜그럴까요? (딱히 에러는 없습니다)

정답을 그대로 써도

WebView에 오류가 생기고 Quick Fix 눌러도 저렇게 세가지 경우만 나와요..

메인 .dart

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:webview_flutter/webview_flutter.dart';


import 'book.dart';
import 'book_service.dart';


void main() {
  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (context) => BookService()),
      ],
      child: const MyApp(),
    ),
  );
}


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


  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: HomePage(),
    );
  }
}


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


  @override
  State<HomePage> createState() => _HomePageState();
}


class _HomePageState extends State<HomePage> {
  var bottomNavIndex = 0;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: [
        SearchPage(),
        LikedBookPage(),
      ].elementAt(bottomNavIndex),
      bottomNavigationBar: BottomNavigationBar(
        selectedItemColor: Colors.black,
        unselectedItemColor: Colors.grey,
        showUnselectedLabels: true,
        selectedFontSize: 12,
        unselectedFontSize: 12,
        iconSize: 28,
        type: BottomNavigationBarType.fixed,
        onTap: (value) {
          setState(() {
            bottomNavIndex = value;
          });
        },
        items: [
          BottomNavigationBarItem(
            icon: Icon(Icons.search),
            label: '검색',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.star),
            label: '좋아요',
          ),
        ],
        currentIndex: bottomNavIndex,
      ),
    );
  }
}


class SearchPage extends StatelessWidget {
  SearchPage({super.key});


  @override
  Widget build(BuildContext context) {
    return Consumer<BookService>(
      builder: (context, bookService, child) {
        return Scaffold(
          appBar: AppBar(
            backgroundColor: Colors.white,
            toolbarHeight: 80,
            title: TextField(
              onSubmitted: (value) {
                bookService.search(value);
              },
              cursorColor: Colors.grey,
              decoration: InputDecoration(
                prefixIcon: Icon(Icons.search, color: Colors.grey),
                hintText: "작품, 감독, 배우, 컬렉션, 유저 등",
                border: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.white),
                  borderRadius: BorderRadius.all(Radius.circular(10)),
                ),
                focusedBorder: OutlineInputBorder(
                  borderSide: BorderSide(color: Colors.grey),
                  borderRadius: BorderRadius.all(Radius.circular(10)),
                ),
              ),
            ),
          ),
          body: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 12),
            child: ListView.separated(
              itemCount: bookService.bookList.length,
              separatorBuilder: (context, index) {
                return Divider();
              },
              itemBuilder: (context, index) {
                if (bookService.bookList.isEmpty) return SizedBox();
                Book book = bookService.bookList.elementAt(index);
                return BookTile(book: book);
              },
            ),
          ),
        );
      },
    );
  }
}


class BookTile extends StatelessWidget {
  const BookTile({
    super.key,
    required this.book,
  });


  final Book book;


  @override
  Widget build(BuildContext context) {
    BookService bookService = context.read<BookService>();


    return ListTile(
      onTap: () {
        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => WebViewPage(
              url: book.previewLink.replaceFirst("http", "https"),
            ),
          ),
        );
      },
      leading: Image.network(
        book.thumbnail,
        fit: BoxFit.fitHeight,
      ),
      title: Text(
        book.title,
        style: TextStyle(fontSize: 16),
      ),
      subtitle: Text(
        book.subtitle,
        style: TextStyle(color: Colors.grey),
      ),
      trailing: IconButton(
        onPressed: () {
          bookService.toggleLikeBook(book: book);
        },
        icon: bookService.likedBookList.map((book) => book.id).contains(book.id)
            ? Icon(
                Icons.star,
                color: Colors.amber,
              )
            : Icon(Icons.star_border),
      ),
    );
  }
}


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


  @override
  Widget build(BuildContext context) {
    return Consumer<BookService>(
      builder: (context, bookService, child) {
        return Scaffold(
          body: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 12),
            child: ListView.separated(
              itemCount: bookService.likedBookList.length,
              separatorBuilder: (context, index) {
                return Divider();
              },
              itemBuilder: (context, index) {
                if (bookService.likedBookList.isEmpty) return SizedBox();
                Book book = bookService.likedBookList.elementAt(index);
                return BookTile(book: book);
              },
            ),
          ),
        );
      },
    );
  }
}


class WebViewPage extends StatelessWidget {
  WebViewPage({super.key, required this.url});


  String url;


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.grey,
        title: Text(url),
      ),
      body: WebView(initialUrl: url),
    );
  }
}

book_service.dart
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';


import 'book.dart';


class BookService extends ChangeNotifier {
  List<Book> bookList = []; // 책 목록
  List<Book> likedBookList = [];


  void toggleLikeBook({required Book book}) {
    String bookId = book.id;
    if (likedBookList.map((book) => book.id).contains(bookId)) {
      likedBookList.removeWhere((book) => book.id == bookId);
    } else {
      likedBookList.add(book);
    }
    notifyListeners();
  }


  void search(String q) async {
    bookList.clear(); // 검색 버튼 누를때 이전 데이터들을 지워주기


    if (q.isNotEmpty) {
      Response res = await Dio().get(
        "https://www.googleapis.com/books/v1/volumes?q=$q&startIndex=0&maxResults=40",
      );
      List items = res.data["items"];


      for (Map<String, dynamic> item in items) {
        Book book = Book(
          id: item['id'],
          title: item['volumeInfo']['title'] ?? "",
          subtitle: item['volumeInfo']['subtitle'] ?? "",
          thumbnail: item['volumeInfo']['imageLinks']?['thumbnail'] ??
              "https://thumbs.dreamstime.com/b/no-image-available-icon-flat-vector-no-image-available-icon-flat-vector-illustration-132482953.jpg",
          previewLink: item['volumeInfo']['previewLink'] ?? "",
        );
        bookList.add(book);
      }
    }
    notifyListeners();
  }
}

book.dart
class Book {
  String id;
  String title;
  String subtitle;
  String thumbnail; // 썸네일 이미지 링크
  String previewLink; // ListTile 을 눌렀을 때 이동하는 링크


  Book({
    required this.id,
    required this.title,
    required this.subtitle,
    required this.thumbnail,
    required this.previewLink,
  });
}