Hero Animation first page

herofirstpage.dart

import 'package:flutter/material.dart';
import 'Second.dart';

void main() => runApp(FlutterAni());

class FlutterAni extends StatelessWidget{

  @override
    Widget build(BuildContext context) {
      // TODO: implement build
      return MaterialApp(
        title: 'Flutter Screen Animation',
        theme: ThemeData(
          primarySwatch: Colors.blue
        ),
        home: FirstScreen(),
      );
    }
}

class FirstScreen extends StatelessWidget{
  @override
    Widget build(BuildContext context) {
      // TODO: implement build
      return Scaffold(
        appBar: AppBar(
          title: Text("Screen Animation"),
        ),
        body: Center(
          child: Container(
            width: 100,
            child: Hero(
              tag: "mainImage",
              child: GestureDetector(
                child: Image.network("https://matwrites.com/wp-content/uploads/2018/03/Flutter.png"),
                onTap: (){
                  Navigator.push(
                    context, 
                    MaterialPageRoute(builder: (context) => Second()));
                },
              ),
            ),
          ),
        ),
      );
    }
}