If you also add it as ClipData, the permission grant will work successfully:
yourIntent.clipData = ClipData.newUri(context.contentResolver, fileName, contentUri)The culprit is that Intent.FLAG_GRANT_READ_URI_PERMISSION will work only for Intent.data and Intent.clipData, and not for extras, unless the uri permission grant has been given explicitly (inconvenient), or has been given by also adding a ClipData.
