如何在 Flutter 中显示 epub 文件的封面图片

Posted 2023-05-06

【中文标题】如何在 Flutter 中显示 epub 文件的封面图片

【英文标题】：How to display Cover Image of an epub file in Flutter

【发布时间】：2021-06-17 20:39:32

【问题描述】：

dart-epub 插件提到了如何获取封面图片的示例：

// Book's cover image (null if there is no cover)
Image coverImage = epubBook.CoverImage;

我怎样才能显示这个？一直报错

The following _TypeError was thrown building:
type 'Image' is not a subtype of type 'ImageProvider<Object>'

【参考方案1】：

更新：我想通了

导入图片和epub包为

import 'package:image/image.dart' as image;
import 'package:epub/epub.dart' as epub;

打开 epub 文件

      // Change the location to wherever your epub file is located
      var targetFile = new File('location/epubFile.epub');
      List<int> bytes = await targetFile.readAsBytes();
      epub.EpubBook epubBook = await epub.EpubReader.readBook(bytes);

将封面图片保存到某个位置（最好是与 epub 文件相同的文件夹，以便一起删除）

// Save the Cover Image to some location
if (await File('location/epubFileCoverImage.png').exists()) 
        print("File exists");
       else 
        try 
          File('location/epubFileCoverImage.png')
              .writeAsBytesSync(image.encodePng(epubBook.CoverImage));
         catch (e) 
          print("Error Saving Cover Image");
          print(e);
          coverError = true;
        
      

使用异常处理，因为加载某些 epub 文件的封面图像可能会出错 最后将其显示在 Widget 树中：

coverError ? Image.asset("assets/Error.png")
           : Image.file(File('location/epubFileCoverImage.png')),