main.dart

import 'package:flutter/material.dart';


void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
    home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
     itemCount:999,
      itemBuilder: (BuildContext ctxt, int index) {
        print(index.toString());
      
     return  Container(height:100,child:Text(index.toString()));
  }  );
  }
}