I'm trying to call Calendar from my simple application in iPhone. all sample out there give me a clue to use UIApplication#openURL function. How about if i want to open a calendar with/without a new event?
'[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel://8004664411"]];'
Apple has a document that lists all of the URL Schemes the current iPhone OS supports. Unfortunately, there isn't one for the calendar, just
so it looks like you can't do it, at least not by launching a URL.
There is currently no API or URL scheme for accessing the calendar information on the phone. If you need one you should file a bug describing why you need it.