title: How to send Whatsapp message to new number
body: <p>I' d like to send a whatsapp message by clicking on a button to a number that comes from the Android Activity (that in turn fetches from a server). 
  The number to which I have to send a new is NOT an existing contact on my phone. 
  I know how to open Whatsapp app from my app. 
  The following piece of code deals with opening whatsapp from an Adapter: </p>
  
  <pre><code>Intent sendIntent = new Intent();
  sendIntent.setPackage("com.whatsapp");
  sendIntent.setAction(Intent.ACTION_SEND);
  sendIntent.putExtra(Intent.EXTRA_TEXT, "This is my text to send.");
  sendIntent.setType("text/plain");
  startActivity(sendIntent);
  </code></pre>
  
  <p>this code opens Whatsapp but I don't know how to pass it the number to which I have to send the message</p>