I am using gdata objectivec client to work with youtube v2.0. I don't want to ask user login many times. I want to login one time and get the accesstoken to use later. Please give me some sample codes to do this. Thanks .
Best way is with the gtm-oauth2 library:
https://code.google.com/p/gtm-oauth2/
Here's a sample app that employs it:
https://github.com/stuffmc/YouTubeSample_iOS
Also reference this SO question:
How to Refresh the token that i got from google oauth 2.0 in iOS