“Cannot find symbol R” error after renaming package name

Question

After renaming my project package name (with Refactor), I got this error:

Error:(7, 44) error: cannot find symbol class R

All of my R

Answer 1

You have to first close android studio. Then

1. Delete "build" folder
2. open the commandline and type gradlew clean
3. Then type gradlew assembledebug
4. If the build succeeds, feel free to go back to android studio