As a black box testing approach, you should not need to know the underlying activity class name, because such information is normally not known unless you look into source code of the application.
When you look at an Android activity, you know which UI screen of the app under test it is, because you recognize the specific title, text or arrangement of UI. I was not suggesting that you should put special elements on your app UI to help test case identify which activity it is; instead, I was suggesting that such matching should be based on existing UI elements of the specific activity that you are trying to capture.