save file issue

[enghussein13]

hi ,
when i run my project and after i save the excel file this error is raised to me:
E/flutter ( 7901): [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: FileSystemException: Creation failed, path = 'Directory: '' (OS Error: Read-only file system, errno = 30)
E/flutter ( 7901): #0 _Directory.createSync (dart:io/directory_impl.dart:133:7)
E/flutter ( 7901): #1 _Directory.createSync (dart:io/directory_impl.dart:128:16)
E/flutter ( 7901): #2 _Directory.createSync (dart:io/directory_impl.dart:128:16)
E/flutter ( 7901): #3 _Directory.createSync (dart:io/directory_impl.dart:128:16)
E/flutter ( 7901): #4 _Directory.createSync (dart:io/directory_impl.dart:128:16)
E/flutter ( 7901): #5 _Directory.createSync (dart:io/directory_impl.dart:128:16)
E/flutter ( 7901): #6 _File.createSync (dart:io/file_impl.dart:270:14)
E/flutter ( 7901): #7 ExcelPage.build. (package:readings_app/excel.dart:55:17)
E/flutter ( 7901):
E/flutter ( 7901):

[FauconSpartiate]

Look at the error message, it says Read-only file system. The OS is denying access to the directory you are saving your file to.
Try saving it somewhere else, or getting the OS to give you access to that directory...