How to Build an Advanced Endless Runner Game Using Flutter, the Casual Games Toolkit, and Back4app

50min
Introduction
Casual games are popular for their simplicity and engaging gameplay, often captivating a wide audience with easy-to-learn mechanics. In this advanced tutorial, we'll develop a fully functional endless runner game using Flutter's Casual Games Toolkit. We'll integrate Back4app to manage the game's backend, storing user data such as high scores, player profiles, and achievements. We'll also delve into advanced topics like state management, performance optimization, and deployment strategies. By the end of this tutorial, you'll have a polished endless runner game ready for deployment on both Android and iOS, complete with data persistence and enhanced features.
Prerequisites
Before you begin, ensure you have the following:
Flutter Development Environment: Installed and configured. Follow the official Flutter installation guide if you haven't set it up.
Intermediate Flutter Knowledge: Familiarity with Flutter widgets, state management, and asynchronous programming.
Back4app Account: Sign up for a free account at Back4app.
Understanding of Back4app: Basic knowledge of creating projects and managing data. Refer to the Back4app getting started guide.
GitHub Account: To clone repositories and manage version control.
Experience with State Management Libraries: Such as Provider or Bloc.
Familiarity with Testing and Deployment: Basic understanding of writing tests and deploying Flutter apps.
﻿
Step 1 – Setting Up Back4app Backend
1.1 Create a New Project on Back4app
Log in to your Back4app account.
Click "Create a new App" and name it "Advanced Endless Runner Game".
1.2 Set Up Classes for User Data
We'll create classes for User, Score, and Achievement.
User Class
Fields:
username (String)
password (String)
email (String)
profilePicture (File)
Score Class
Fields:
user (Pointer to User)
highScore (Number)
level (Number)
Achievement Class
Fields:
user (Pointer to User)
achievementName (String)
dateAchieved (Date)
1.3 Configure Security and Permissions
Set class-level permissions to secure user data.
Ensure that only authenticated users can read and write their own data.
1.4 Add Sample Data
Populate the classes with sample data to test the integration later.
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Step 2 – Cloning and Setting Up the Endless Runner Template
2.1 Clone the Flutter Casual Games Toolkit Repository
Bash
git clone https://github.com/flutter/casual-games.git
git clone https://github.com/flutter/casual-games.git
﻿
2.2 Navigate to the Endless Runner Template
Bash
cd casual-games/templates/endless_runner
cd casual-games/templates/endless_runner
﻿
2.3 Open the Project in Your IDE
Use Visual Studio Code, Android Studio, or any preferred IDE.
Ensure that Flutter and Dart plugins are installed.
2.4 Update Dependencies
Open pubspec.yaml and update dependencies to the latest versions.
Run:
Bash
flutter pub get
flutter pub get
﻿
﻿
Step 3 – Enhancing the Game with Advanced Features
3.1 Implement User Authentication
We'll allow players to sign up, log in, and manage their profiles.
3.1.1 Add Parse Server SDK
In pubspec.yaml:
YAML
dependencies:
  parse_server_sdk_flutter: ^3.1.0
dependencies:
  parse_server_sdk_flutter: ^3.1.0
﻿
Run:
Bash
flutter pub get
flutter pub get
﻿
3.1.2 Set Up Authentication Service
Create lib/services/auth_service.dart:
Dart
import 'package:parse_server_sdk_flutter/parse_server_sdk_flutter.dart';

class AuthService {
  Future<ParseUser> signUp(String username, String password, String email) async {
    var user = ParseUser(username, password, email);
    var response = await user.signUp();
    if (response.success) {
      return response.result;
    } else {
      throw Exception(response.error!.message);
    }
  }

  Future<ParseUser> logIn(String username, String password) async {
    var user = ParseUser(username, password, null);
    var response = await user.login();
    if (response.success) {
      return response.result;
    } else {
      throw Exception(response.error!.message);
    }
  }

  Future<void> logOut() async {
    var user = await ParseUser.currentUser() as ParseUser;
    await user.logout();
  }
}
import 'package:parse_server_sdk_flutter/parse_server_sdk_flutter.dart';

class AuthService {
  Future<ParseUser> signUp(String username, String password, String email) async {
    var user = ParseUser(username, password, email);
    var response = await user.signUp();
    if (response.success) {
      return response.result;
    } else {
      throw Exception(response.error!.message);
    }
  }

  Future<ParseUser> logIn(String username, String password) async {
    var user = ParseUser(username, password, null);
    var response = await user.login();
    if (response.success) {
      return response.result;
    } else {
      throw Exception(response.error!.message);
    }
  }

  Future<void> logOut() async {
    var user = await ParseUser.currentUser() as ParseUser;
    await user.logout();
  }
}
﻿
3.1.3 Create Authentication Screens
Sign Up Screen: lib/screens/signup_screen.dart
Login Screen: lib/screens/login_screen.dart
Use Flutter widgets to create forms for user input.
3.2 Enhance UI/UX
Implement custom animations using AnimationController.
Add a custom theme in lib/theme.dart.
3.3 Add Achievements and Leaderboards
Create UI components to display achievements.
Implement a leaderboard screen to display top scores globally.
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Step 4 – Integrating Back4app with the Game
4.1 Initialize Parse in main.dart
Dart
void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  const keyApplicationId = 'YOUR_APP_ID';
  const keyClientKey = 'YOUR_CLIENT_KEY';
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
  );

  runApp(MyApp());
}
void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  const keyApplicationId = 'YOUR_APP_ID';
  const keyClientKey = 'YOUR_CLIENT_KEY';
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
  );

  runApp(MyApp());
}
﻿
4.2 Securely Store Credentials
Use flutter_dotenv to manage environment variables.
In pubspec.yaml:
YAML
dependencies:
  flutter_dotenv: ^5.0.2
dependencies:
  flutter_dotenv: ^5.0.2
﻿
Create a .env file (add it to .gitignore):
Text
APP_ID=YOUR_APP_ID
CLIENT_KEY=YOUR_CLIENT_KEY
APP_ID=YOUR_APP_ID
CLIENT_KEY=YOUR_CLIENT_KEY
﻿
Update main.dart:
Dart
import 'package:flutter_dotenv/flutter_dotenv.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await dotenv.load(fileName: ".env");

  final keyApplicationId = dotenv.env['APP_ID']!;
  final keyClientKey = dotenv.env['CLIENT_KEY']!;
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
  );

  runApp(MyApp());
}
import 'package:flutter_dotenv/flutter_dotenv.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await dotenv.load(fileName: ".env");

  final keyApplicationId = dotenv.env['APP_ID']!;
  final keyClientKey = dotenv.env['CLIENT_KEY']!;
  const keyParseServerUrl = 'https://parseapi.back4app.com';

  await Parse().initialize(
    keyApplicationId,
    keyParseServerUrl,
    clientKey: keyClientKey,
    autoSendSessionId: true,
  );

  runApp(MyApp());
}
﻿
Step 5 – Implementing State Management
5.1 Choose a State Management Solution
We'll use Provider for simplicity.
5.1.1 Add Provider Dependency
In pubspec.yaml:
YAML
dependencies:
  provider: ^6.0.0
dependencies:
  provider: ^6.0.0
﻿
Run:
Bash
flutter pub get
flutter pub get
﻿
5.2 Create Game State Management
5.2.1 Create Game State Class
lib/models/game_state.dart:
Dart
import 'package:flutter/foundation.dart';

class GameState extends ChangeNotifier {
  int _score = 0;
  int get score => _score;

  void incrementScore() {
    _score++;
    notifyListeners();
  }

  void resetScore() {
    _score = 0;
    notifyListeners();
  }
}
import 'package:flutter/foundation.dart';

class GameState extends ChangeNotifier {
  int _score = 0;
  int get score => _score;

  void incrementScore() {
    _score++;
    notifyListeners();
  }

  void resetScore() {
    _score = 0;
    notifyListeners();
  }
}
﻿
5.2.2 Provide Game State
In main.dart:
Dart
import 'package:provider/provider.dart';
import 'models/game_state.dart';

void main() async {
  // ... Parse initialization

  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => GameState()),
      ],
      child: MyApp(),
    ),
  );
}
import 'package:provider/provider.dart';
import 'models/game_state.dart';

void main() async {
  // ... Parse initialization

  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => GameState()),
      ],
      child: MyApp(),
    ),
  );
}
﻿
**5.2.3
Consume Game State in Widgets**
In your game screen:
Dart
int score = context.watch<GameState>().score;
int score = context.watch<GameState>().score;
﻿
Step 6 – Optimizing Performance
6.1 Game Performance
Sprite Management: Use sprite sheets to reduce memory usage.
Frame Rate Optimization: Limit the frame rate to balance performance and battery life.
6.2 Network Optimization
Data Caching: Implement caching mechanisms to reduce network calls.
Batch Requests: Use batch operations when communicating with the backend.
6.3 Code Profiling
Use Flutter's DevTools to profile the app.
Identify and fix performance bottlenecks.
Step 7 – Robust Error Handling and Testing
7.1 Error Handling
Try-Catch Blocks: Wrap asynchronous calls to handle exceptions.
Dart
try {
  var result = await someAsyncFunction();
} catch (e) {
  // Handle error
}
try {
  var result = await someAsyncFunction();
} catch (e) {
  // Handle error
}
﻿
User Feedback: Display user-friendly messages when errors occur.
7.2 Logging
Use the logging package to log errors and important events.
In pubspec.yaml:
YAML
dependencies:
  logging: ^1.0.2
dependencies:
  logging: ^1.0.2
﻿
7.3 Testing
7.3.1 Unit Tests
Write tests for your models and services.
Example test in test/game_state_test.dart:
Dart
import 'package:flutter_test/flutter_test.dart';
import 'package:your_app/models/game_state.dart';

void main() {
  test('Score increments correctly', () {
    final gameState = GameState();
    gameState.incrementScore();
    expect(gameState.score, 1);
  });
}
import 'package:flutter_test/flutter_test.dart';
import 'package:your_app/models/game_state.dart';

void main() {
  test('Score increments correctly', () {
    final gameState = GameState();
    gameState.incrementScore();
    expect(gameState.score, 1);
  });
}
﻿
7.3.2 Integration Tests
Test the app's UI and interactions.
Use Flutter's integration testing framework.
Step 8 – Deploying the Game
8.1 Preparing for Deployment
App Icons and Splash Screens: Customize for branding.
App Bundle IDs: Set unique identifiers for Android and iOS.
8.2 Build Release Versions
Android
Update android/app/build.gradle with your signing configs.
Run:
Bash
flutter build apk --release
flutter build apk --release
﻿
iOS
Open ios/Runner.xcworkspace in Xcode.
Set up signing and capabilities.
Run:
Bash
flutter build ios --release
flutter build ios --release
﻿
8.3 App Store Submission
Google Play Store: Follow the official guide.
Apple App Store: Follow the official guide.
Conclusion
In this advanced tutorial, we've built a feature-rich endless runner game using Flutter's Casual Games Toolkit and integrated Back4app for backend services. We've covered:
User Authentication: Allowing players to sign up, log in, and manage profiles.
State Management: Using Provider for efficient state management.
Performance Optimization: Enhancing game and network performance.
Error Handling and Testing: Implementing robust error handling and writing tests.
Deployment: Preparing and submitting the app to app stores.
This comprehensive approach equips you with the skills to develop professional-grade Flutter applications with reliable backend integrations. You can further expand the game by adding more features, such as:
Social Sharing: Allow players to share achievements on social media.
In-App Purchases: Monetize the game with purchasable items or upgrades.
Multiplayer Support: Implement real-time or turn-based multiplayer functionality.
For more information on Flutter and Back4app integration, refer to:
﻿Flutter Documentation﻿
﻿Back4app Flutter Guide﻿
﻿Parse Server Guides﻿
Happy coding and game development!
Updated 13 Sep 2024
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