All these solutions are outdated. It's really easy now in Android Studio:
File > New Module...
The next screen looks weird, like you are selecting some widget or something but keep it on the first picture and below scroll and find "Import JAR or .AAR Package"
Then take Project Structure
from File menu.Select app
from the opened window then select dependencies
,then press green plus button
,select module dependency
then select module you imported then press OK