Type androidx.appcompat.resources.R$dimen is defined multiple times

Got the same problem, just clean project and rebuild again.

I had same issue after updating gradle version to 3.6.3 from 3.5.2 in Android Studio.

I have multiple Build Variants.

I fixed the issue by first deleting .gradle folder from the project and did Clean Project and Rebuild Project.

If you have multiple build variant you may have to do same thing for each one when you change build variants from one to another.

Igor Montella's comment to my question fixed the problem - downgrade to gradle plugin 3.5.0.