title: How to query in a Flutter/FirebaseAnimatedList using buildArguments or anything else? (example please)
body: <p>I have a this <code>Scaffold</code> with body:</p>
  
  <pre><code>body: new Column(
          children: &lt;Widget&gt;[
            new Flexible(
              child: new FirebaseAnimatedList(
                query: FirebaseDatabase.instance
                    .reference()
                    .child('products')
                    .orderByChild('order'),
                padding: new EdgeInsets.all(8.0),
                reverse: false,
                itemBuilder: (_, DataSnapshot snapshot,
                    Animation&lt;double&gt; animation, int x) {
                  return new ProductItem(
                      snapshot: snapshot, animation: animation);
                },
              ),
            ),
          ],
        ),
  </code></pre>
  
  <p>but I need to add a simple query:  <code>'Active' = true</code></p>
  
  <p>Is it possible? How? Any example/tutorial?</p>
  
  <p>Thanks.</p>