Replace Override App Bar Back Button In Flutter Android

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    debugShowCheckedModeBanner: false,
    title: 'Flutter Navigate to Next Screen',
    home: FirstScreen(),
  ));
}

class FirstScreen extends StatelessWidget {
  gotoNextActivity(BuildContext context){
    Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => SecondScreen()),
    );
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Color(0xFF880E4F),
        title: Text('Home Activity Screen'),
      ),
      body: Center(
        child: RaisedButton(
            child: Text('Navigate To Second Screen'),
            color: Colors.pink,
            textColor: Colors.white,
            onPressed: () {
              gotoNextActivity(context);
            }),

      ),
    );
  }
}
class SecondScreen extends StatelessWidget {
  goBack(BuildContext context){
    Navigator.pop(context);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          backgroundColor: Color(0xFF880E4F),
          automaticallyImplyLeading: true,
          title: Text('OverRide AppBar BACK Button'),
          leading: IconButton(icon:Icon(Icons.home),
            onPressed: () {goBack(context);},
          )
      ),

      body: Center(
        child: RaisedButton(
          onPressed: () {goBack(context);},
          color: Colors.pink,
          textColor: Colors.white,
          child: Text('Go Back To Previous Screen'),
        ),
      ),
    );
  }
}