title: How to access the Widget from within its own callback (onPressed) in Dart/Flutter
body: <p>I have the following code:</p>
  
  <pre><code>  @override
    Widget build(BuildContext context) {
      return new Container(
        height: 72.0, // in logical pixels
        padding: const EdgeInsets.symmetric(horizontal: 8.0, vertical: 8.0),
        decoration: new BoxDecoration(color: Colors.white),
        // Row is a horizontal, linear layout.
        child: new MaterialButton(
          child: new Text(
            _sprinkler.name,
            style: new TextStyle(color: Colors.white)
            ),
          splashColor: Colors.blueAccent,
          color: Colors.blue[800],
          onPressed: () {
            print("onTap(): tapped" + _sprinkler.name);
          },
        ),
      );
    }
  </code></pre>
  
  <p>onPressed(), I want to change the Buttons style - to represent sprinkler activity.</p>
  
  <p>Therefore, I would need to acces the MaterialButton Widget itself.</p>
  
  <p>But how to I access it from within the callback?</p>
  
  <p>Thanks a lot in advance, and sorry for the n00b question, I am new to Dart and Flutter ;)</p>