title: Calculate how much DPI width does device have
body: <p>In <a href="http://developer.android.com/guide/practices/screens_support.html" rel="nofollow">Android documentation</a> says, that I can use alternate resources for devices that (for example) has minimum available width in dp units at which the resources should be used—defined by the  value. </p>
  
  <p>So by creating "w720dp" folder, creates resources for particular tablets.
  I would like to know how programatically calculate how much width does particular device have.</p>
  
  <p>Thanks in advance!</p>