[移动开发]Flutter Web读写文件

Read:
Use this library to select a file:?pub.dev/packages/file_picker?(Web migration guide)

import 'dart:html' as webFile;
import 'package:file_picker_web/file_picker_web.dart' as webPicker;

if (kIsWeb) {
   final webFile.File file = await webPicker.FilePicker.getFile(
      allowedExtensions: ['pd'],
      type: FileType.custom,
   );
  
   final reader = webFile.FileReader();
   reader.readAsText(file);

   await reader.onLoad.first;

   String data = reader.result;
}

Write?(a.k.a download):

import 'dart:html' as webFile;

if (kIsWeb) {
   var blob = webFile.Blob(["data"], 'text/plain', 'native');

   var anchorElement = webFile.AnchorElement(
      href: webFile.Url.createObjectUrlFromBlob(blob).toString(),
   )..setAttribute("download", "data.txt")..click();
}