title: How do I add a border to a flutter button?
body: <p>I've just recently gotten into flutter and am loving it so far but I've gotten stuck on some UI changes. Any help is appreciated!</p>
  <p>My goal is to get a circular button that has an icon with a blue background but then have a border around the outside that is a darker blue. There are pictures attached.</p>
  <p>My approach was:</p>
  <ol>
  <li>Get a circular blue button.</li>
  <li>Put an icon in that button.</li>
  <li>Add a border.</li>
  </ol>
  <p>I got stuck on step 3 because I do not know how to add a border, or if it is even possible given the way I approached the problem. The specific colors do not matter to me at the moment, I will change the theme later.</p>
  <p>This is what I currently have code wise:</p>
  <pre><code>  var messageBtn = new Row(
    children: &lt;Widget&gt;[
      new Padding(
        padding: const EdgeInsets.all(20.0),
        child: new RawMaterialButton(
          onPressed: _messages,
          child: new Padding(
            padding: const EdgeInsets.all(20.0),
            child: new Icon(
              Icons.message,
              size: 30.0,
              color: Colors.white,
            ),
          ),
          shape: new CircleBorder(),
          fillColor: Colors.deepPurple,
        ),
      ),
      new Padding(
          padding: const EdgeInsets.all(8.0),
          child: new Text(
            'Send Messages',
            style: new TextStyle(
              fontSize: 20.0,
            ),
          )),
    ],
  );
  </code></pre>
  <p>It produces this: <img src="https://i.stack.imgur.com/5cVyd.png" alt="see screenshot" /></p>
  <p>I want this:<img src="https://i.stack.imgur.com/vpZww.png" alt="see second screenshot" /></p>