Flutter Convert Int Variable To String Data Type App

import 'package:flutter/material.dart';

void main(){
  runApp(MyApp());
}
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: MyHomePage(),
    );
  }
}
class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin {
  int value = 2034567890 ;
  String holder ;
  changeType(){
    setState(() {
      holder = value.toString();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        backgroundColor: Colors.pink[900],
        title: Text('Convert Int Integer Variable'),
      ),
            body: Center(
                child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: <Widget>[

                      Container(
                          padding: EdgeInsets.fromLTRB(0, 10, 0, 10),
                          child: Text('$value', style: TextStyle(fontSize: 22,color: Colors.white),)),

                      RaisedButton(
                        onPressed: () => changeType(),
                        child: Text('Convert Int Type to String on Button Click'),
                        textColor: Colors.white,
                        color: Colors.pink[900],
                        padding: EdgeInsets.fromLTRB(10, 10, 10, 10),
                      )

                    ]))
    );
  }
}