Hi!
We've tried several SSO implementations and integrated Screens with
some of them... the easiest way would be using a token based
authentication (using OAuth or independently) between the portal and
the mobile application... (I know it means lots of changes and configurations)
I would also try with the cookie mode, login normally to the portal
inside the application and use that cookie to do request to the
JSON-WS services.
Other easy, although more cumbersome for the users and fragile, would
be logging a webview inside the android application and intercepting
the credentials to do a request to the JSON-WS services.
