title: Android - OnDateChangedListener - how do you set this?
body: <p>There is an event listener in Android called <strong>DatePicker.OnDateChangedListener</strong>. 
  I am trying to set a DatePicker view's on date changed listener as follows:</p>
  
  <pre><code>DatePicker dp = new DatePicker(getContext());
  dp.setOnDateChangedListener(this); 
  //where this is my activity extends DatePicker.OnDateChangedListener
  </code></pre>
  
  <p>But guess what? 
  Date picker does not have a method called <strong>setOnDateChangedListener</strong>.</p>
  
  <p>My question is: </p>
  
  <ol>
  <li>How then do you set a date changed listener in Android?  </li>
  <li>If it is not possible to set a date changed listener, what is the purpose for this event?</li>
  </ol>
  
  <p>Any documentation/tutorials will be very helpful.</p>