title: Issue with AlertDialog being triggered by a button
body: <p>I am trying to have an alert dialogue appear after I click a button but clicking the button doesn't do anything for some reason. I have it in the onPressed so I'm not sure why it isn't triggering. Also if I get this working will it work with Apple devices as well since this is a materials widget. </p>
  
  <pre><code>class AddButton extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        body: Container(
          alignment: Alignment.bottomCenter, // align the row
          child: Row(
            children: &lt;Widget&gt;[
              Expanded(
                child: RaisedButton(
                  onPressed: (){
                    AlertDialog(
                      title: Text("Test"),
                      content: Text("This is a test..."),
                      elevation: 24.0,
                    );
                  },
                  color: Colors.blue,
                  splashColor: Colors.white,
                  elevation: 2,
                )
              )
            ],
          )
        )
      );
    }
  }
  </code></pre>