AndroidStudio cannot resolve symbol for anything

Question

I have an android project that I've been working on with no issues for a while. Now all of the sudden when I open it, every file is showing false errors. I get "cannot resolve symbol" for everything.

It still builds and runs correctly, but it's very annoying to have the red lines on every line of code. I've tried deleting the project and pulling it back down from GitHub, restarting AndroidStudio, and I even uninstalled/reinstalled AndroidStudio. Nothing works. Any suggestions?

Answer 1

I too had this problem. All I did was go to File, then invalidate cache/restart and it worked.