The layout in layout has no declaration in the base layout folder [error]

Question

After migrating to Android Studio 3.2, API 28, I am getting the following error on my app\'s layout:

The layout in layout has no declaration in the base lay

Answer 1

In my case this warning appeared due to "wrong" character (dot) used in value name:

24dp

Removing dots (right click on a name, then Refactor-Rename in Android Studio) resolved the problem.