Swift write/save/move a document file to iCloud drive

Question

I\'ve been trying for over two days to write a file to iCloud drive. I have tried writing a simple text file directly, locally then moving it, using UIDocumentMenuViewContro

Answer 1

Maybe there's a rule for container's name.
I tried the following names.

○:iSheet
×:sheetFiles
×:com.myname.sheetFiles