Im trying to access youtube account with account manager, meaning i want to access youtube with a account linked to my device and with this get youtube token to access user
I haven't used it myself in an app yet, and it might not be available on all Android devices, but my understanding is that the Google Play services now provides the best approach to getting OAuth 2 tokens (including those scoped to https://gdata.youtube.com). There's more info at
http://android-developers.blogspot.com/2012/09/google-play-services-and-oauth-identity.html
You could go with the AccountManager approach for wider compatibility, though.