import 'dart:math'; import 'package:flutter/material.dart'; void main() => runApp( MaterialApp( home: BallPage(), ), ); class BallPage extends StatelessWidget { @override Widget build(BuildContext context) { return Scaffold( backgroundColor: Colors.blue, appBar: AppBar( backgroundColor: Colors.blue.shade900, title: Text('Ask Me Anything'), ), body: Ball(), ); } } class Ball extends StatefulWidget { @override _BallState createState() => _BallState(); } class _BallState extends State { int ballNumber = 1; @override Widget build(BuildContext context) { return Center( child: FlatButton( onPressed: () { ballNumber = Random().nextInt(5); print(ballNumber); }, child: Image.asset('images/ball1.png'), ), ); } }