I have been successfully syncing my gmail account (mail, contacts, and calendar) with my iphone for several years now. Recently, my secondary calendars have stopped being able to be accessed through the native calendar app. I don't know why.
I've gone here: https://www.google.com/calendar/iphoneselect?pli=1 and checked all of my calendars, but still only the main one syncs. My company uses google calendar to keep track of my comings and goings, and they're going to make me switch to Android if I don't get this sorted out SOON!
Thanks for any help!
I figured it out.
If anyone happens to come here via a search, here's the answer:
I had set up my Gmail account in my phone as an "exchange" account so that it pushes the mail. That was the problem with the calendar. It only synced one calendar.
I just turned off the "calendar" part of my "exchange" account (gmail) and then added a second gmail account (not as exchange, but as Gmail) and chose to only sync the calendar. This made the phone use exchange to push the email, and CalDAV to push all of my google calendars.
That was complicated.