The method 'FlatButton' isn't defined for the class 'UpdateMenu'.

[clovett]

Launching lib\main.dart on Chrome in debug mode...
lib/screens/update_menu.dart:33:13: Error: The method 'FlatButton' isn't defined for the class 'UpdateMenu'.

• 'UpdateMenu' is from 'package:getx_restaurant/screens/update_menu.dart' ('lib/screens/update_menu.dart').
  Try correcting the name to the name of an existing method, or defining a method named 'FlatButton'.
  FlatButton(
  ^^^^^^^^^^
  Failed to compile application.

[tataDan]

I got the same error. Apparently FlatButton is deprecated. I changed the relevant code to this:

// FlatButton(
            TextButton(
              style: ButtonStyle(
                  foregroundColor:
                      MaterialStateProperty.all<Color>(Colors.deepOrange)),
              child: const Text(
                "Submit",
                style: TextStyle(color: Colors.white),
              ),
              onPressed: () => {},
              // color: Colors.deepOrange,
            ),

The error disappeared and the application ran. However, I am not certain that this is the best way to resolve the issue.