flutter app导出excel

要在Flutter应用程序中导出Excel文件并在其中显示图片，你可以使用syncfusion_flutter_xlsio插件。该插件支持将文本和图片写入Excel文件。首先，你需要将在线图片地址转换为Uint8List格式。你可以使用dio库下载图片并将其转换为Uint8List，然后使用syncfusion_flutter_xlsio插件将其写入Excel文件中。以下是一个示例代码：

import 'dart:io';
import 'package:image/image.dart' as imgLib;
import 'package:dio/dio.dart';
import 'dart:convert';
import 'package:syncfusion_flutter_xlsio/xlsio.dart' as Flutter_xlsio;
import 'package:path_provider/path_provider.dart' as path_provider;

Future<Uint8List> downloadImage(String imageUrl) async {
  Dio dio = Dio();
  Response response = await dio.get(imageUrl, options: Options(responseType: ResponseType.bytes));
  return response.data;
}

void exportExcelWithImage() async {
  // 创建一个新的Excel文档
  Flutter_xlsio.Workbook workbook = Flutter_xlsio.Workbook();
  Flutter_xlsio.Worksheet sheet = workbook.worksheets[0];
  
  // 下载并转换图片
  Uint8List imageBytes = await downloadImage('https://example.com/image.jpg');
  imgLib.Image image = imgLib.decodeImage(imageBytes);
  imgLib.Image resizedImage = imgLib.copyResize(image, width: 100, height: 100);
  Uint8List resizedImageBytes = imgLib.encodeJpg(resizedImage);
  
  // 将图片插入Excel文件
  sheet.insertImage(1, 1, resizedImageBytes);
  
  // 保存Excel文件
  String filePath = (await path_provider.getTemporaryDirectory()).path + '/exported_excel.xlsx';
  await workbook.saveAs(filePath);  
  print('Excel文件已导出到：$filePath');
}

exportExcelWithImage();