SecondScreen | Better screen mirroring for Android devices

import 'package:flutter/material.dart';
import 'package:flutter_bmi_app/second_screen.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';

class BmiCalc extends StatefulWidget {
  const BmiCalc({Key? key}) : super(key: key);

  @override
  State createState() => _BmiCalcState();
}

class _BmiCalcState extends State {
  Color colorOfLittleBox = Color.fromARGB(255, 27, 28, 48);
  Color colorOfLittleBox2 = Colors.pink;
  bool isMale = true;

  double _value = 150;
  int weight = 60;
  int age = 25;
  double answer = 10;
  String calc = "CALCULATE";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Color.fromARGB(255, 12, 9, 34),
      body: SafeArea(
        child: SingleChildScrollView(
          child: Column(
            children: [
              Row(
                children: [
                  FemaleBox("MALE", Icons.male),
                  FemaleBox("FEMALE", Icons.female),
                ],
              ),
              Column(children: [
                Container(
                    padding: EdgeInsets.all(32),
                    margin: EdgeInsets.all(10),
                    decoration: BoxDecoration(
                      color: Color.fromARGB(255, 27, 28, 48),
                      borderRadius: BorderRadius.circular(15),
                    ),
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        const Text("HEIGHT",
                            style: TextStyle(color: Colors.grey, fontSize: 20)),
                        const SizedBox(
                          height: 10,
                        ),
                        Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Text(_value.toStringAsFixed(0),
                                style: const TextStyle(
                                    fontSize: 45,
                                    color: Colors.white,
                                    fontWeight: FontWeight.w900)),
                            const Text(
                              "cm",
                              style:
                                  TextStyle(fontSize: 20, color: Colors.grey),
                            ),
                          ],
                        ),
                        Slider(
                          min: 100,
                          max: 230,
                          thumbColor: Colors.pink,
                          value: _value,
                          onChanged: (value) {
                            setState(() {
                              _value = value;
                            });
                          },
                        ),
                      ],
                    ))
              ]),
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Operation("Weight"),
                  Operation("Age"),
                ],
              ),
              Container(
                decoration: BoxDecoration(
                  color: Colors.pink,
                  borderRadius: BorderRadius.circular(15),
                ),
                padding: EdgeInsets.only(bottom: 5),
                width: MediaQuery.of(context).size.width,
                child: TextButton(
                  child: Text(
                    calc,
                    style: const TextStyle(
                        fontSize: 22,
                        color: Colors.white,
                        fontWeight: FontWeight.w900),
                  ),
                  onPressed: () {
                    Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => SecondScreen()),

                    );
                  },
                ),
              )
            ],
          ),
        ),
      ),
    );
  }

  void calculate() {
    answer = (weight / (_value * _value)) * 10000;
    Text(answer.toString(),
        style: const TextStyle(fontSize: 40, color: Colors.white));
    if (calc == "CALCULATE") {
      calc = answer.toStringAsFixed(1);
    } else {
      calc = "CALCULATE";
    }
    setState(() {});
  }