Error adding items

I am creating a project and wouldn’t like to use a database, just add items and be stored in runtime.
However, I don’t know how to create their UUID and I am getting this error:
'There was an exception while trying to navigate to ‘home/null/edit’ with the exception message ‘Invalid UUID string: null’

Can you share your code if you are still having the issue? Most likely you need to initialize the id with something like UUID.randomUUID()