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

I had an issue after copy/pasting code into an XML layout file, but I fixed it by just manually creating the file. Very strange, since the code was exactly the same, but somehow it fixed this issue. I did try restarting and doing the "File => Invalidate Caches / Restart => Invalidate and Restart" fix, but the issue was only fixed by manually recreating the file.