how to validate entered password and confirm password are same in flutter

Question

I am trying to validate the values of password field and confirm password field. how to validate entered password and confirm password are same in flutter.

The edited text value could not be taken as value so couldn't find the solution.

import 'package:flutter/material.dart';
import 'package:form_field_validator/form_field_validator.dart';
import 'package:loginform_validation_demo/LoginFormWithValidation.dart';
import 'validation.dart';
import 'HomePage.dart';

class SignupPage extends StatelessWidget {
  GlobalKey<FormState> formkey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        elevation: 0,
        brightness: Brightness.light,
        backgroundColor: Colors.white,
        leading: IconButton(
            onPressed: () {
              Navigator.pop(context);
            },
            icon: Icon(
              Icons.arrow_back_ios,
              size: 20,
              color: Colors.black,
            )),
      ),
      body: SafeArea(
        child: Form(
          autovalidateMode: AutovalidateMode.always,
          key: formkey,
          child: SingleChildScrollView(
            child: Container(
              height: MediaQuery.of(context).size.height,
              width: double.infinity,
              child: Column(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Column(
                    children: [
                      Column(
                        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                        children: [
                          SizedBox(
                            height: 40,
                          ),
                          Text(
                            "Sign up",
                            style: TextStyle(
                              fontSize: 30,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          SizedBox(
                            height: 20,
                          ),
                          Text(
                            "Create an Account,Its free",
                            style: TextStyle(
                              fontSize: 15,
                              color: Colors.grey[700],
                            ),
                          ),
                          SizedBox(
                            height: 30,
                          )
                        ],
                      ),
                      Padding(
                        padding: EdgeInsets.symmetric(horizontal: 40),
                        child: Column(
                          children: [
                            usernameMakeInput(label: "User Name"),
                            passwordMakeInput(label: "Password", obsureText: true),
                            passwordMakeInput(label: "Confirm Password", obsureText: true)
                          ],
                        ),
                      ),
                      Padding(
                        padding: EdgeInsets.symmetric(horizontal: 40),
                        child: Container(
                          height: 50,
                          width: 200,
                          child: MaterialButton(
                            minWidth: double.infinity,
                            height: 50,
                            onPressed: () {
                              if (formkey.currentState.validate()) {

                                Navigator.push(
                                    context,
                                    MaterialPageRoute(
                                        builder: (_) => HomePage()));
                                print("Validated");
                              } else {
                                print("Not Validated");
                              }
                            },
                            color: Colors.blue,
                            shape: RoundedRectangleBorder(
                                borderRadius: BorderRadius.circular(20)),
                            child: Text(
                              "Sign Up",
                              style: TextStyle(
                                  fontWeight: FontWeight.w600,
                                  fontSize: 18,
                                  color: Colors.white),
                            ),
                          ),
                        ),
                      ),
                      SizedBox(
                        height: 20,
                      ),
                      Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          Text(
                            "Already have an account?",
                            style: TextStyle(fontSize: 15),
                          ),
                          TextButton(
                            onPressed: () {
                              Navigator.push(
                                context,
                                MaterialPageRoute(
                                    builder: (context) =>
                                        LoginFormValidation()),
                              );
                            },
                            child: Text(
                              'Login',
                              style:
                                  TextStyle(color: Colors.blue, fontSize: 18),
                            ),
                          ),
                        ],
                      )
                    ],
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

validation:

This is the part where I try to pass the edit text value

Widget passwordMakeInput({label, obsureText = false}) {
  return Column(
    crossAxisAlignment: CrossAxisAlignment.start,
    children: [
      Text(
        label,
        style: TextStyle(
            fontSize: 15, fontWeight: FontWeight.w400, color: Colors.black87),
      ),
      SizedBox(
        height: 5,
      ),
      TextFormField(
        onChanged: (value){

        },
          maxLength: 6,
          obscureText: obsureText,
          decoration: InputDecoration(
            contentPadding: EdgeInsets.symmetric(vertical: 0, horizontal: 10),
            border: OutlineInputBorder(),
          ),
          validator: MultiValidator([
            RequiredValidator(errorText: "* Required"),
            MinLengthValidator(6,
                errorText: "Password should contain 6 characters"),
          ])),
      SizedBox(
        height: 30,
      )
    ],
  );
}