title: How add sharedpref into Retrofit interface
body: <p>I need to get the following URL with Retrofit, <code>mensajes.php?cel=NUMBER</code>, How i can do for add the <strong>NUMBER</strong> from <em>sharedpref</em>, in this case Will be <code>user.getCel ()</code></p>
  
  <p>My interface code with Retrofit is this:</p>
  
  <pre><code>public interface ApiInterface {
  
      @GET("mensajes.php?cel=")
      Call&lt;List&lt;Message&gt;&gt; getInbox();
  }
  </code></pre>
  
  <p>I noob, thnks for you help.</p>