Flutter - SimpleDialog in FloatingActionButton

I noticed the accepted answer is using child for showDialog which is actually deprecated, so I would recommend avoiding it. You should be using builder instead, I've provided an example:

onPressed: () {
    showDialog(
        context: context,
        builder: (_) => AlertDialog(
            title: Text('Dialog Title'),
            content: Text('This is my content'),
        )
    );
}

You need to wrap this on a show action dialog.

showDialog(context: context, builder: (BuildContext context) {
   return new AlertDialog(
      title: new Text("My Super title"),
      content: new Text("Hello World"),
   );
}