How to use conditional statement within child attribute for Expanded Widget, Flutter

I want the Expanded widget to change dependent on 'Button 1', 'Button 2' or "Button 3' is pressed. The buttons is just text wrapped in a InkWell, I can change this, but it is only for purpose of understanding how to make the Expanded to be defendant on the button push.

I have read quite a few post on this, but it is not clear to me how to do this.

IF there is a better way to do this, please tell me.

Your help is appreciated.

import 'package:flutter/material.dart'; double selectedScreen = 1; void main() { runApp(const MyApp()); } class MyApp extends StatelessWidget { const MyApp({super.key}); // This widget is the root of your application. @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, ), home: const MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatefulWidget { const MyHomePage({super.key, required this.title}); final String title; @override State<MyHomePage> createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget middleScreen() { if (selectedScreen == 1) { return FirstScreen(); } else if (selectedScreen == 2) { return SecondScreen(); } else { return ThirdScreen(); } } Container FirstScreen() { return Container(child: Text('FirstScreen')); } Container SecondScreen() { return Container(child: Text('SecondScreen')); } Container ThirdScreen() { return Container(child: Text('ThirdScreen')); } Widget build(BuildContext context) { return Scaffold( body: Center( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Row( mainAxisAlignment: MainAxisAlignment.spaceEvenly, children: [ InkWell( onTap: () { selectedScreen = 1; }, child: Column( children: [ Text( 'Buttonn 1', ), ], ), ), InkWell( onTap: () { selectedScreen = 2; }, child: Column( children: [ Text( 'Button 2', ) ], ), ), InkWell( onTap: () { selectedScreen = 3; }, child: Column( children: [ Text( 'Button 3', ) ], ), ), ], ), Container( height: 30, ), Row( mainAxisAlignment: MainAxisAlignment.spaceEvenly, children: [Expanded(child: middleScreen())], ) ], ), ), ); } }