I have Android client to my AppEngine server, both using Google Accounts. I would like to use AccountManager for getting accessToken for OAuth. So far I’m using ClientLogin, but I would like to switch to OAuth.
Setting up OAuth on AppEngine is easy – I followed this article. But the client side is a mystery, in particular I don’t know what to use for scope, in AccountManager terms authTokenType. For ClientLogin, I’m using “ah” for authTokenType. But what about OAuth?
As of today you can use Google Play Services API on android to do Oauth 2.0 authentication on android. You could then use the method described by @nivco to get the userinfo on appengine. I have not done this yet, but I plan tp do exactly what your talking about.
https://developers.google.com/android/google-play-services/authentication