title: Flutter stretch columns to full screen height
body: <p>All three elements are at the top of the screen and stretch to fill the width, but I want them to stretch to fill the screen vertically from top to bottom.</p>
  
  <p>I tried adding a <code>Row</code> around everything but it throws the error <code>RenderFlex children have non-zero flex but incoming width constraints are unbounded</code>? So I tried wrapping that <code>Row</code> in an <code>Expanded</code> widget which throws the error 'Expanded widgets must be placed inside Flex widgets'.</p>
  
  <pre><code>return Scaffold(
    backgroundColor: Color(0xFF222222),
    body: Column(
    children: &lt;Widget&gt;[
      SizedBox(height: 20),
      Row(
        // crossAxisAlignment: CrossAxisAlignment.stretch,//throws error
        children: &lt;Widget&gt;[
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: &lt;Widget&gt;[
                Container(
                  color: Colors.red,
                  child: Text('Left', textAlign: TextAlign.center),
                ),
              ],
            ),
          ),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: &lt;Widget&gt;[
                Container(
                  color: Colors.red,
                  child: Text('Right', textAlign: TextAlign.center),
                ),
              ],
            ),
          ),
        ],
      ),
      Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: &lt;Widget&gt;[
          Container(
            color: Colors.red,
            child: Text('Bottom', textAlign: TextAlign.center),
          ),
        ],
      ),
    ],
  ),
  );
  </code></pre>