Here’s how we used Rails Admin to only allow a field to be shown after creation.
We have a client who wanted the ability to be able to edit slugs (appropriate warnings were given about how this can be a bad thing!). We only wanted this field to be visible on edit in Rails Admin as we normally generate our slugs from the model’s title attribute.
RailsAdmin.config do |config| config.model Article do edit do field :slug do visible do bindings[:object].slug.present? end help "WARNING, if you edit this - old links to the article WILL break" # just in case they forget! end end end end