Building a Multiplatform Game Using Flutter and Back4app

introduction flutter is a versatile open source framework by google that allows developers to build natively compiled applications for mobile, web, desktop, and embedded devices from a single codebase although flutter is primarily known for traditional app development, it is increasingly being used for game development due to its performance, extensive package ecosystem, and hot reload functionality in this guide, we will walk through how to develop a multiplatform flappy bird style game using flutter and flame, a game engine designed for 2d games in flutter additionally, we will connect the game to back4app, a backend as a service (baas) platform, to store user scores and display a leaderboard by the end of this guide, you will have a working version of the game that runs on mobile and web platforms, and it will store and retrieve high scores from back4app prerequisites to complete this tutorial, you will need a back4app account sign up for a free account at back4app com https //www back4app com a flutter development environment is set up on your local machine follow the flutter installation guide https //flutter dev/docs/get started/install if you haven't set it up yet basic knowledge of dart, flutter widgets, and game development concepts step 1 – setting up your back4app backend create a back4app project log in to your back4app account https //dashboard back4app com/ and create a new project create parse classes for this tutorial, we’ll set up a simple backend for managing game related data in your back4app project, create two parse classes named player and gamescore player stores player information such as username, level, and achievements gamescore stores scores and rankings for the game get your back4app credentials navigate to your project settings to retrieve your application id and client key, which you’ll need to connect your flutter game to back4app step 2 – setting up your flutter project create a new flutter project open your terminal or command prompt and run add dependencies open pubspec yaml and add the following dependencies initialize parse in your app in lib/main dart , import the parse sdk and initialize it in the main function import 'package\ flutter/material dart'; import 'package\ parse server sdk flutter/parse server sdk flutter dart'; import 'package\ flame/flame dart'; import 'package\ flame/game dart'; void main() async { widgetsflutterbinding ensureinitialized(); const keyapplicationid = 'your back4app app id'; const keyclientkey = 'your back4app client key'; const keyparseserverurl = 'https //parseapi back4app com'; await parse() initialize(keyapplicationid, keyparseserverurl, clientkey keyclientkey, autosendsessionid true); runapp(mygameapp()); } class mygameapp extends statelesswidget { @override widget build(buildcontext context) { return materialapp( home gamescreen(), ); } } replace 'your back4app app id' and 'your back4app client key' with your actual back4app credentials step 3 – setting up the game using flame create the game class flame is an open source game engine built on top of flutter it provides tools and apis for building 2d games create a simple game class using flame import 'package\ flame/game dart'; import 'package\ flame/components dart'; class mysimplegame extends flamegame { @override future\<void> onload() async { super onload(); add(playercomponent()); } } class playercomponent extends positioncomponent { @override future\<void> onload() async { // load player sprite or set up player visuals here size = vector2(50, 50); // set size of the player position = vector2(100, 100); // set initial position // optionally, add sprite or animations } @override void update(double dt) { // update player state here } @override void render(canvas canvas) { super render(canvas); // draw player visuals final paint = paint() color = colors blue; canvas drawrect(size torect(), paint); } } 2\ create the game screen update the gamescreen widget to display the game class gamescreen extends statelesswidget { @override widget build(buildcontext context) { return scaffold( body mysimplegame() widget, ); } } 3\ run the game you can now run your app using flutter run to see your simple game in action you should see a blue square representing the player step 4 – managing game data with back4app saving player data next, let's create a function to save player data to back4app when the player levels up or achieves something future\<void> saveplayerdata(string username, int level, list\<string> achievements) async { final player = parseobject('player') set('username', username) set('level', level) set('achievements', achievements); final response = await player save(); if (response success) { print('player data saved successfully'); } else { print('failed to save player data'); } } 2\ retrieving high scores you can also fetch the high scores for your game from back4app to display on a leaderboard future\<list\<parseobject>> fetchhighscores() async { final query = querybuilder\<parseobject>(parseobject('gamescore')) orderbydescending('score') setlimit(10); final response = await query query(); if (response success && response results != null) { return response results as list\<parseobject>; } else { print('failed to fetch high scores'); return \[]; } } 3\ display the leaderboard use listview\ builder in a flutter widget to display the top 10 scores class leaderboardscreen extends statefulwidget { @override leaderboardscreenstate createstate() => leaderboardscreenstate(); } class leaderboardscreenstate extends state\<leaderboardscreen> { list\<parseobject> highscores = \[]; @override void initstate() { super initstate(); fetchhighscores() then((scores) { setstate(() { highscores = scores; }); }); } @override widget build(buildcontext context) { return scaffold( appbar appbar(title text('leaderboard')), body listview\ builder( itemcount highscores length, itembuilder (context, index) { final score = highscores\[index]; return listtile( title text(score get\<string>('playerid') ?? 'unknown player'), subtitle text('score ${score get\<int>('score')}'), ); }, ), ); } } step 5 – adding advanced features with flame if you want to add more complex game mechanics, animations, or interactions, you can expand your use of flame by introducing additional components such as sprites, physics, and collision detection flame also supports integrating with firebase, enabling multiplayer features, in app purchases, and more conclusion in this tutorial, you learned how to use flutter and flame to build a simple multiplatform game and how to integrate back4app for managing game data such as player profiles and high scores flutter's ability to deploy to multiple platforms from a single codebase, combined with back4app's robust backend services, makes this a powerful stack for developing and scaling games whether creating a simple casual game or a more complex interactive experience, flutter and back4app provide the tools to build, deploy, and manage your game efficiently for more information, check out the flutter documentation https //flutter dev/docs and the back4app documentation https //www back4app com/docs happy coding!