connection in our odoo database

I would like to have an offer for the realization of this project( it is necessary just connected a android application to odoo). Our Project : Our android (4.1) application have three pages, the first page contains three Edit Text(URL,username and password)and a button "do_connection", firstly we have to write the right url of our server then the username and password, when we click to do_connection, it must check the existance of information in our database, if the information are correct so the second page appears with a comment "welcome user". the second page contains two buttons (enter and exist),first when we click enter our application records the exact date and the exact hour of user access to our server second when we click exist our application records the exact date and the exact hour of user logout from our server. our majeur problem is how to connect our application to our server and activate the afromentioned buttons. Best regards,