I need to read a file from app A's File.DirDefaultExternal in app B. I don't want to send the file to App B, I just want to read it, (so that once i uninstall App A, i won't be able to read it from App B). How is this done in B4A?
You can use Runtimepermission and write it somewhere on the external sdcard. Use runtimepermissions in the other app too and check the specific path for the file.
For sure you should not use a restricted path. File.DirInternal can not be read by any other app for ex.