How can I reference user inputted data in a different file?

Question

I am creating an app in Flutter and I would like to store and reference a user's name in future dart files. I am currently working on the account setup, and the first dart file contains a textfield where the user must enter in their name. I want to be able to show that user inputted name in a different file, but I am unsure of how to do so. Any help is greatly appreciated!

Where the user inputs their name

Where I want their name to go in a new dart dile

Answer 1

Update: I figured it out! A linked post gave me a hint. (How can I navigate between 2 classes, one of them requires passing data? in flutter)

Since I already had a controller defined for a different application, I couldn't use TextController(). Instead, I created an empty string and stored the textfield input in it. I then saved it as an argument in RouteSettings(), then used an if/else statement and ModalRoute() to pull the user-inputted value. Thank you everyone for your help!

I've attached chunks of my code :)

class _NamePageState extends State<NamePage> {
  String _nickname = "";
}

// Creation of TextField
TextField(
                        onChanged: (val) {
                          setState(() {
                            _nickname = val;
                          });
                        },
)

// Elevated Button info
ElevatedButton(onPressed: isButtonActive
                ? () {
                  Navigator.push(context,
                  PageTransition(
                    type: PageTransitionType.rightToLeftJoined,
                    duration: const Duration(milliseconds: 650),
                    child: const SelectionScreen(),
                    childCurrent: widget,
                    settings: RouteSettings(
                      arguments: _nickname)
                  ),);

// Second dart file calling TextField parameter
 Widget build(BuildContext) {
    double _height = MediaQuery.of(context).size.height;
    final data = ModalRoute.of(context)!.settings;

    String retrieveString;

    if (data.arguments == null) {
      retrieveString = "empty";
    } else {
      retrieveString = data.arguments as String;
    }

// Text being shown
Text('Hello there $retrieveString!)