Is using System Hungarian Notation for Android UI components (Views) valid? I mean using it ONLY for Views - no strSomething, boolStuff or similar names.

For example, tvDescription (TextView), editUsername or txtUsername (EditText), btnSubmit (Button), etc.

Especially with Buttons, because btnStartCountdown seems better than startCountdown - it sounds like a function minus the parentheses, and it's difficult to know that it's a Button by its name alone.