title: How to check if the screen hasn't been clicked in Android?
body: <p>I know that if you want to check if someone clicked on something, you would do </p>
  
  <pre><code>if(event.getAction() == MotionEvent.ACTION_DOWN)
  </code></pre>
  
  <p>But I want to check if the screen hasn't been clicked at all.
  What is the code I would produce in order to do this?</p>
  
  <p>Also, as a side note, would it be a good idea to have all the classes in an Android app extend the <code>View</code> classes?</p>