Android Studio - XML Editor autocomplete not working with support libraries

If NONE of the above answers worked, ...

Just navigate to your android studio installation directory, i.e,

yourDrive:/.AndroidStudio3.3/system

and DELETE THE CACHE FOLDER ( first close android studio, if its running ).

Then start Android Studio again. Done.

P.S I am using android studio 4.0

I have tried a lot of things (restart Android Studio, PC, Invalidate Caches, Power Saver mode,...).

Finally, deleting the .idea folder and all .iml files from the project, restarting Android Studio, and rebuilding Gradle did the trick. Autocomplete in XML support library is working again.

Checking out files from Version Control or copying all the source files in a new project would do the trick as well.

The answer for me was to switch to lower sdk when compiling projec, I think this is platform problem. I was using sdk 33.

Change in build.gradle

compileSdk=32