title: Get WhatsApp messages
body: <p>Is it possible to create a listener to get a message from <strong>whatsApp</strong> in android?<br>
  I mean like you have a <code>broadcastReceiver</code> to listen to incoming SMS in android...</p>
  
  <p>Is any API is needed for that thing, or is it legal thing to do or I need to get any permission from <code>whatsApp</code>?</p>