Hello, I am a fresh owner of a Volla Phone with Ubuntu Touch installed. I installed Waydroid with the app Waydroid Helper. It works good and i have no problems to use android apps.
For a better experience i would like to mount a shared folder, to share files. Both, the filemanager of Ubuntu Touch and Waydroid should have read and write access to this folder.
I found this solution:
https://docs.waydro.id/faq/setting-up-a-shared-folder

sudo mount --bind <source> ~/.local/share/waydroid/data/media/0/<target>

But I didn't get it to work. So I searched and found this solution:

lxc.mount.entry = <source> data/media/0/<target> none bind,rw 0 0

I added this line to the lxc configuration file config_nodes and it worked. I can now move files in Waydroid to the folder and have this files in the Ubuntu Touch home directory source folder. The problem is now, that i have now no write access to this folder. The owner and group changed form phablet:phablet to 1023:1023 and i cannot change owner and group with chown. For instance I mounted the filesystem of Ubuntu Touch r/w.

I found out, that the problem is to map uids and gids. This is done with idmap in the lxc config file, but this very complicate. Does someone know how to do or managed this already?