how to pass variables into a stateful widget? – Flutter

I’m trying to learn how to pass variables into a stateful widget.

here is my code:

class TestTest extends StatefulWidget {
  final String selectedText;
  const TestTest({Key? key, required this.selectedText,})
      : super(key: key);

  @override
  State<TestTest> createState() => _TestTestState();
}

class _TestTestState extends State<TestTest> {
  String optionAData = '';
  String optionBData = '';
  @override
  Widget build(BuildContext context) {
    switch (selectedText) {
      case 'OptionA':
        return Column(
          children: [
            WidgetDisplay1(
              onTap: (){
                setState(() {
                  optionAData = 'A123';
                });
              },
            ),
            WidgetDisplay3(
              onTap: (){
                setState(() {
                  optionAData = 'A456';
                });
              },
            ),
          ],
        );
      case 'OptionB':
        return Column(
          children: [
            WidgetDisplay5(
              onTap: (){
                setState(() {
                  optionBData = 'B123';
                });
              },
            ),
            WidgetDisplay3(onTap: (){
              setState(() {
                optionBData = 'B456';
              });
            }),
            WidgetDisplay4(
              onTap: (){
                setState(() {
                  optionBData = 'B789';
                });
              },
            ),
          ],
        );
      default:
        return Container();
    }
  }
}

this is how i’ve been told to do it but the selectedText beside the Switch key word is returning the error: Undefined name ‘selectedText’. which I thought I had defined at the top of the class with the final string selectedText.

Thanks so much and any help would be greatly appreciated.