title: Alignment with Stack in flutter
body: <h3>Project</h3>
  <p>Hi,
  I was trying to align some widgets inside a Stack in Flutter. My end result was something like:
  <a href="https://i.stack.imgur.com/aKSbB.png" rel="noreferrer"><img src="https://i.stack.imgur.com/aKSbB.png" alt="enter image description here" /></a></p>
  <p>I know that this can be easily achieved with a Row but I want to animate the position ot the two children so I'm forced to use stack.</p>
  <p>My problem is simple:</p>
  <h3>Example code</h3>
  <pre><code>return Container(
    child: Stack(
      children: &lt;Widget&gt;[
        Align(
          alignment: Alignment.centerLeft,
          child: _buildSign(),
        ),
        Align(
          alignment: Alignment.centerRight,
          child: _buildSign(),
        ),
      ],
    ),
  );
  </code></pre>
  <p>This will not render as I expected. No matter what I put in the <code>alignment</code> field: <code>Alignment.centerRight</code> and <code>Alignment.centerLeft</code> will always place the child to the center left.</p>
  <p>The problem is solved only if I give a fixed width to the wrapping container. Now I understand why this happend but what if I want the container to be the size of his childrens? Label is a dynamic text so his width is unpredictable for me</p>
  <p>Any ideas?</p>
  <p>Thanks</p>