Cannot find R.layout.activity_main

Question

I was trying to work out with multiple layout using some online tutorials. The thing is my program was building and compiling correctly as long as there was only one XML fil

Answer 1

what I tried:

1. check every XML file for some famous known errors.
2. cleaned the project multiple times.
3. synced Gradle with the project file.

What Worked:

1. Invalidate caches and restart.