Foreign key referencing a view in Oracle

Regardless the possibility of creating foreign keys to views, it is indeed not the best idea to implement.

Database views were designed to let user comfortably query some data he needs, but at the same time to serve as a security barrier, to conceal all database structure, including tables, data constraints in tables, and, yes, also table cross-references.

So, a good practice to me would be to reference an existing table from a your new one, despite its residence in other scheme.