title: Created a Stateful widget and not being able to setstate()
body: <p>Building first flutter app and having some trouble implementing this class</p>
  <p>I'm pretty sure its a Stateful Widget, I've created a build method so it should be an implementation of createState() but I'm still getting this error on the name of the class. Because of this error I cant setState() a global list Im adding to.</p>
  <p>Error below:</p>
  <blockquote>
  <p>Missing concrete implementation of 'StatefulWidget.createState'. Try
  implementing the missing method, or make the class abstract.</p>
  </blockquote>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>class TransactionSubmission extends StatefulWidget {
  
    final controllerForNumPad = NumpadController(format: NumpadFormat.CURRENCY);
  
    Widget build(BuildContext context) {
      return Scaffold(
          appBar: AppBar(
            title: Text("Submit your transaction!"),
          ),
          body: Container(
            //padding: EdgeInsets.all(0.0),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: &lt;Widget&gt;[
                Padding(
                    padding: EdgeInsets.all(50.0),
                    child: NumpadText(
                        controller: controllerForNumPad,
                        style: TextStyle(fontSize: 50))),
                Expanded(
                    child: Numpad(
                        buttonColor: Colors.blue,
                        controller: controllerForNumPad,
                        buttonTextSize: 35)),
                Row(
                    mainAxisSize: MainAxisSize.min,
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: &lt;Widget&gt;[
                      Padding(
                          padding: EdgeInsets.all(8.0),
                          child: RaisedButton(
                              padding: const EdgeInsets.all(10.0),
                              color: Colors.blue,
                              onPressed: () {
                                //String temp = controllerForNumPad.formattedString;
                                Navigator.push(
                                    context,
                                    MaterialPageRoute(
                                        builder: (context) =&gt;
                                            ReportsPage()));
                              },
                              child: Text("Reports",
                                  style: TextStyle(fontSize: 25)))),
                      SizedBox(
                          width: 250,
                          child: RaisedButton(
                              onPressed: () {
                                Navigator.push(
                                    context,
                                    MaterialPageRoute(
                                        builder: (context) =&gt; ReportsPage()));
                                ReportsPage._key.currentState
                        .setTodo(Transaction(total: controllerForNumPad.formattedString));
                    setState(() {
  
                    });
                                controllerForNumPad.clear();
                              },
                              textColor: Colors.white,
                              padding: const EdgeInsets.all(10.0),
                              color: Colors.blue,
                              child:
                                  Text("Submit", style: TextStyle(fontSize: 25))))
                    ])
              ],
            ),
          ));
    }
  }</code></pre>
  </div>
  </div>
  </p>