flutter || Navigate to a new screen

import 'package:flutter/material.dart';
void main(){
  runApp(MaterialApp(home: FirstPage(),));
}

class FirstPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        appBar: AppBar(title: Text("hello"),),
        body: Center(
          child: RaisedButton(
            child: Text("click"),
            onPressed: (){
              Navigator.push(context, MaterialPageRoute(builder: (context)=>SecondPage()));
            },
          ),
        ),
      ),

    );
  }
}
class SecondPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.red,
        title: Text("Second Page"),
      ),
    );
  }
}