title: Android application login
body: <p>Can somebody help me in suggesting some good tutorial where I can start. 
  I want to build a simple application with a dashboard and a login screen. For the first time user is asked for a log-in screen. login check is carried out via a POST call to a remote PHP script. Once the user is logged in he/she should be redirected to dashboard. Once the user closes and reopens the application he'she should be redirected to login screen.</p>
  
  <p>i know how to create forms and how to post, help is needed in the area of switching layouts based on user roles and how to import/extend classes, for example I prefer to have a separate log in (activity) class. but this login class need to be imported to Main (main should extend Activity)</p>