Android Studio 3.0 cannot resolve symbol Theme

Question

As stated in style.xml, there is a weird error, which shows Cannot resolve symbol 'Theme', which is quite strange.

See pic of the error :-

My Project Specs:-

Using Android Studio 3.0

and gradle version 3.0.0

and distributionUrl=https://services.gradle.org/distributions/gradle-4.1-all.zip

Edit:-

Tried clearing the cache by going to File > Invalidate Cache/Restart > Invalidate and Restart, but to no avail, as the error persists.

Answer 1

Had the same issue after upgrading to Android Studio 3.1 (EDIT: bug still present at v3.1.3). What worked for me was clicking File > Close Project and then reopening the project from Studio's dialog.