title: How to implement a tri state button using Qt
body: <p>I need to create a button which has three states:</p>
  
  <ul>
  <li>unclicked</li>
  <li>intermediate</li>
  <li>clicked</li>
  </ul>
  
  <p>The logic I want to implement with this button is that whenever this button is clicked, I want the system to go to the intermediate state and wait for an event.</p>
  
  <p>In other way when the state transition is <code>unclicked --&gt; intermediate -- &gt; clicked</code> and then <code>clicked --&gt; intermediate --&gt;unclicked</code>.</p>
  
  <p>Does Qt support implementing this kind of button? If so, how?</p>