Flutter ListView Item and Detail Click Listener

Main.dart

import 'package:flutter/material.dart';

void main() =>
    runApp(MaterialApp(home: Scaffold(appBar: AppBar(), body: sta())));

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

  @override
  State<sta> createState() => _staState();
}

var isShow = false;
var getdata = Diohelper.getdata();

class _staState extends State<sta> {
  @override
  Widget build(BuildContext context) {
    List mwidge = [];
    int index = 0;
    getdata.forEach((element) {
      element.index = index;
      mwidge.add(ListTile(
        onTap: () {
          Navigator.push(context,
              MaterialPageRoute(builder: (context) => DetailPage(element)));
        },
        hoverColor: Colors.amber,
        title: Text(element.name.toString()),
        trailing: element.isShow
            ? SizedBox(
                width: 100,
                height: 50,
                child: OutlinedButton(
                    onPressed: () {
                      Scaffold.of(context).showSnackBar(
                          SnackBar(content: Text(element.name.toString())));
                    },
                    child: Text("Show")),
              )
            : Container(
                width: 100,
              ),
      ));
      index++;
    });
    return GestureDetector(
      child: Center(
        child: ListView(
          children: [...mwidge],
        ),
      ),
    );
  }
}

class DetailPage extends StatefulWidget {
  productModel model;

  DetailPage(this.model, {Key? key}) : super(key: key);

  @override
  _DetailPageState createState() => _DetailPageState();
}

class _DetailPageState extends State<DetailPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(),
        body: Container(
          child: ListView(
            children: [
              Text("Name:" + widget.model.name.toString()),
              Text("Category:" + widget.model.category.toString()),
              Text("price:" + widget.model.price.toString())
            ],
          ),
        ));
  }
}

class productModel {
  String? name;
  String? price;
  String? category;
  bool isShow = false;
  int index = 0;

  productModel({this.name, this.price, this.category, this.isShow = false});

  productModel.fromJson(Map<String, dynamic> json) {
    name = json['name'];
    price = json['price'];
    category = json['category'];
    isShow = json['isShow'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    data['price'] = this.price;
    data['category'] = this.category;
    data['isShow'] = this.isShow;
    return data;
  }
}

class Diohelper {
  static List<productModel> getdata() {
    List<productModel> list = [];
    list.add(productModel(name: "broast", price: "100", category: "chicken"));
    list.add(productModel(name: "mandi", price: "100", category: "chicken"));
    list.add(productModel(name: "mandi", price: "100", category: "veg"));

    return list;
  }
}