At the moment (12 Sep 2018), it seems to be possible to synchronize with Google Calendar (CalDAV) using DAVdroid.
Please note that synchronization with Google is not officially supported by Google or DAVdroid. For some people it seems to work, for others it doesn't.
Using DAVdroid with Google does not provide any additional privacy or other advantages in comparison to the default Google synchronization, but you can use it without having GApps and/or a Google account on your device.
firstname.lastname@example.org by your Google account)
If you need another calendar than the main calendar, you have to find out the calendar ID (something like
email@example.com) and use this base URL:
User name and password: your Google account
Please have a look into our forums for up-to-date information: