[android] Error:(9, 5) error: resource android:attr/dialogCornerRadius not found

Had the same issue while working on an application with several modules, check to make sure as you increase the compileSdkVersion and targetSdkVersion to 28+ values in a module you also do for the others.

A module was running on compileSdkVersion 29 and targetSdkVersion 29 while a second module of the application was running on compileSdkVersion 27 and targetSdkVersion 27.

Changing the second module to also compile for and target SDK version 29 resolved my issue. Hope this helps someone.