Something for you interested..
Google+ Platform Java API Starter Project
These starter projects demonstrate use of the Google+
APIs and development best practices. You can use them as a starting point for building your own Google+
applications.
These starter projects are the easiest way to get up and running with each library. They include everything needed to use OAuth authentication and demonstrate a few simple API calls. Even though some languages may not have starter projects, you can still use those libraries with Google+
. Check the project home page for the library for instructions on how to get started.
They are available for these platforms:
* Command line
* Google AppEngine
* J2EE web application
* Android
Also play with LiveDemo
UPDATE:
Yes, you can integrate LinkedIn
to your android application.
LinkedIn
LinkedIn
provides a REST based API.
you can code to that API using the Apache HTTP Client
visit the LinkedIn
Developers site here
also this might be helpful (I am not familiar with it, though):
http://code.google.com/p/jlinkedin-linkedin-java-api/
Also Here is the sample project and Source-Code
Also look at this SO Question Posting LinkedIn message from Android application and LinkedIn integration with Android..
Thanks...