Flutter电子书阅读插件lentera_epub_viewer的使用

lentera_epub_viewer 是一个用于在 Flutter 应用程序中显示 EPUB 文件的插件。它封装了 folioreader 框架，并支持 iOS 和 Android 平台。

特性

截图

浅色模式

深色模式

安装

要使用该插件，首先确保你的项目配置正确。在 iOS 上，你需要安装 Swift，并且最低部署目标为 9.0。

在 pubspec.yaml 文件中添加依赖：

dependencies:
  lentera_epub_viewer: latest_version

注意：请在 Android 的发布构建类型中添加以下代码以避免发布版本崩溃：

minifyEnabled false
shrinkResources false

在 AndroidManifest.xml 中添加必要的权限：

<uses-permission android:name="android.permission.INTERNET" />
<application
    xmlns:tools="http://schemas.android.com/tools"
    android:usesCleartextTraffic="true"
    android:requestLegacyExternalStorage="true"
    android:networkSecurityConfig="@xml/network_security_config"
    android:exported="true">
</application>

在 android/app/src/main/res/xml 目录下创建 network_security_config.xml 文件，并添加以下内容：

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">your_domain.com</domain>
    </domain-config>
</network-security-config>

使用

在 Dart 代码中，你可以使用以下方法来初始化和打开 EPUB 文件：

import 'package:lentera_epub_viewer/epub_viewer.dart';

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

class MyApp extends StatefulWidget {
  [@override](/user/override)
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool loading = false;
  String filePath = "";

  [@override](/user/override)
  void initState() {
    download();
    super.initState();
  }

  download() async {
    // 下载 EPUB 文件
    Directory? appDocDir = await getExternalStorageDirectory();
    String path = appDocDir!.path + '/sample.epub';
    File file = File(path);

    if (!file.existsSync()) {
      await file.create();
      await dio.download(
        "https://vocsyinfotech.in/envato/cc/flutter_ebook/uploads/22566_The-Racketeer---John-Grisham.epub",
        path,
        deleteOnError: true,
        onReceiveProgress: (receivedBytes, totalBytes) {
          setState(() {
            loading = true;
          });
        },
      ).whenComplete(() {
        setState(() {
          loading = false;
          filePath = path;
        });
      });
    } else {
      setState(() {
        loading = false;
        filePath = path;
      });
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(
          title: const Text('EPUB Reader Example'),
        ),
        body: Center(
          child: loading
              ? Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    CircularProgressIndicator(),
                    Text('Downloading.... E-pub'),
                  ],
                )
              : Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    ElevatedButton(
                      onPressed: () async {
                        if (filePath == "") {
                          download();
                        } else {
                          EpubViewer.setConfig(
                            themeColor: Theme.of(context).primaryColor,
                            identifier: "iosBook",
                            scrollDirection: EpubScrollDirection.ALLDIRECTIONS,
                            allowSharing: false,
                            enableTts: true,
                            nightMode: true,
                          );

                          // 获取当前读取位置
                          EpubViewer.locatorStream.listen((locator) {
                            print('LOCATOR: $locator');
                          });

                          EpubViewer.open(
                            filePath,
                            lastLocation: EpubLocator.fromJson({
                              "bookId": "2239",
                              "href": "/OEBPS/ch06.xhtml",
                              "created": 1539934158390,
                              "locations": {"cfi": "epubcfi(/0!/4/4[simple_book]/2/2/6)"}
                            }),
                          );
                        }
                      },
                      child: Text('Open Downloaded E-pub'),
                    ),
                    ElevatedButton(
                      onPressed: () async {
                        EpubViewer.setConfig(
                          themeColor: Theme.of(context).primaryColor,
                          identifier: "iosBook",
                          scrollDirection: EpubScrollDirection.ALLDIRECTIONS,
                          allowSharing: false,
                          enableTts: true,
                          nightMode: true,
                        );

                        // 获取当前读取位置
                        EpubViewer.locatorStream.listen((locator) {
                          print('LOCATOR: $locator');
                        });

                        await EpubViewer.openAsset(
                          'assets/4.epub',
                          lastLocation: EpubLocator.fromJson({
                            "bookId": "2239",
                            "href": "/OEBPS/ch06.xhtml",
                            "created": 1539934158390,
                            "locations": {"cfi": "epubcfi(/0!/4/4[simple_book]/2/2/6)"}
                          }),
                        );
                      },
                      child: Text('Open Assets E-pub'),
                    ),
                  ],
                ),
        ),
      ),
    );
  }
}