main.dart

class _MyHomePageState extends State<MyHomePage> {
  final fb = FirebaseDatabase.instance;
  final myController = TextEditingController();
  final name = "Name";

  @override
  Widget build(BuildContext context) {
    final ref = fb.reference();
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Container(
            child: Column(
          children: <Widget>[
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: <Widget>[
                Text(name),
                SizedBox(width: 20),
                Expanded(child: TextField(controller: myController)),
              ],
            ),
          ElevatedButton(
              onPressed: () {
                ref.child(name).set(myController.text);
              },
              child: Text("Submit"),
            ),
          ],
        )));
  }

  @override
  void dispose() {
    // Clean up the controller when the widget is disposed.
    myController.dispose();
    super.dispose();
  }
}