getting following error "R cannot be resolved to a variable"

Question

I recently update android sdk and having following error R cannot be resolved to a variable. I cleaned and build project but R file still missing. i also install Android SDK build tools but R cannot be resolved. How can I resolve this problem. I saw another articles but these wasn't help me.

Answer 1

Change the version from 2.2 to 4.4 or whatever then clean the project and the error will be removed.