Cannot resolve symbol 'Theme' Validates resource references inside Android XML files

Question

After upgrading android studio to 3.1, in old projects I have a problem - Cannot resolve symbol 'Theme'

Cannot resolve symbol 'Theme' Validates resource references inside Android XML files

I tried to do a lot of things but I still see the same problem. What I've done: *sync project with gradle files; *invalidate cache and restart; *Bild, Rebild project; *compared gradle version in AS (4.4 - 3.1.0) and in a project (3.1.0) - the same; order of repositories google() jcenter() and I did many other things but I don't have result( who knows how to solve?

Answer 1

Close the project from the File menu and open the project again as existing Android Studio project. This worked for me.