I am using google calendar API to sync google calendar with our custom calendar. Right now I am trying it with a crude way by asking user if he/she wants to sync their calendar with google or not. If they say "yes" , I show them login screen where they have to enter their google user id and password and the calendar will be synced. But now when I change the month , the screen gets refreshed and all login information is lost and that changed month doesn't show up the events from google calendar.

What is a best way for authentication AuthSub, OAuth or the crude way I mentioned for testing locally? I really don't know if I can use OAuth locally.