🧮 Calculator Flutter

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Calculator is your essential tool for all your mathematical needs. With a clean and user-friendly interface, this app is designed to make both simple and complex calculations easy and efficient. Whether you're a student, professional, or just need quick calculations on the go, Calculator provides accurate results every time. Powered by Flutter, it offers a smooth and reliable experience across all your devices. Simplify your math with Calculator!

📱 ScreenShot

✨ Features

🔢 Calculator Modes

• Standard Calculator: Basic arithmetic operations with a clean, intuitive interface
• Scientific Calculator: Advanced mathematical functions including trigonometry, logarithms, powers, and more
• Expression Parsing: Supports complex expressions with proper precedence handling like (1+1)*2/2+(8*8)

📱 User Experience

• Responsive Design: Optimized for all screen sizes and orientations
• Dark & Light Themes: Beautiful themes that adapt to system preferences or manual selection
• Calculation History: Save, search, and replay past calculations
• Material Design 3: Modern UI following the latest design guidelines

🔧 Technical Features

• Firebase Integration: Performance monitoring and crash analytics
• Google Play Integrity API: Enhanced security and fraud prevention
• State Management: Efficient state management using Provider pattern
• Local Storage: Persistent settings and history using SharedPreferences
• Error Handling: Robust error handling for invalid expressions
• Performance Optimized: Smooth animations and fast calculations

🚀 Getting Started

Prerequisites

• Flutter SDK (>=3.9.2)
• Dart SDK (comes with Flutter)
• Android Studio or VS Code with Flutter extensions
• Java JDK (for Android development)
• Firebase project (for analytics and crash reporting)

Quick Setup

1. Clone the repository

   git clone https://github.com/muhammad-fiaz/Calculator-Flutter.git
   cd Calculator-Flutter

2. Install dependencies

   flutter pub get

3. Configure Firebase (optional)

   • Create a Firebase project at Firebase Console
   • Add Android and iOS apps to your project
   • Download configuration files:
     • google-services.json → android/app/
     • GoogleService-Info.plist → ios/Runner/
   • Enable services: Analytics, Crashlytics, Performance Monitoring

4. Run the app

   # Debug mode
   flutter run
   
   # Release mode (requires signing config)
   flutter run --release

Platform-Specific Setup

Android Development

# Check Android setup
flutter doctor --android-licenses

# Build APK
flutter build apk --release

# Build App Bundle (recommended for Play Store)
flutter build appbundle --release

iOS Development (macOS only)

# Install iOS dependencies
cd ios && pod install && cd ..

# Build for iOS
flutter build ios --release

Web Development

# Enable web support
flutter config --enable-web

# Run on web
flutter run -d chrome

# Build for web
flutter build web --release

Desktop Development

# Windows
flutter config --enable-windows-desktop
flutter run -d windows

# macOS
flutter config --enable-macos-desktop
flutter run -d macos

# Linux
flutter config --enable-linux-desktop
flutter run -d linux

📐 Calculator Functions

Standard Operations

• Basic arithmetic: +, -, ×, ÷
• Decimal numbers with proper validation
• Percentage calculations
• Parentheses for grouping: (, )

Scientific Functions

• Trigonometry: sin, cos, tan (supports both radians and degrees)
• Logarithms: ln (natural log), log (base 10)
• Powers: x², x³, xʸ, √x
• Advanced: x! (factorial), 1/x (reciprocal)
• Constants: π (pi), e (Euler's number)

Expression Examples

(2 + 3) × 4 = 20
sin(30°) = 0.5
log(100) = 2
2³ + √16 = 12
5! = 120

🎨 Themes

Light Theme

• Clean, bright interface
• High contrast for readability
• Material Design 3 color system

Dark Theme

• Easy on the eyes
• Battery-friendly for OLED displays
• Consistent with system dark mode

System Theme

• Automatically follows system settings
• Seamless transitions between modes

📊 History & Analytics

Calculation History

• Persistent Storage: All calculations are saved locally
• Search Functionality: Find specific calculations quickly
• Filter by Mode: View standard or scientific calculations
• Statistics: Track usage patterns and calculation frequency
• Export: Export history for backup (coming soon)

Firebase Analytics

• Performance Monitoring: Track app performance and optimization
• Crash Reporting: Automatic crash detection and reporting
• Usage Analytics: Understand feature usage patterns

🏗️ Architecture

State Management

• Provider Pattern: Clean separation of business logic and UI
• Multiple Providers: Separate providers for calculator, history, and theme
• Reactive UI: Automatic UI updates when state changes

Project Structure

lib/
├── main.dart                 # App entry point
├── providers/               # State management
│   ├── calculator_provider.dart
│   ├── history_provider.dart
│   └── theme_provider.dart
├── screens/                 # UI screens
│   ├── main_screen.dart
│   ├── calculator_screen.dart
│   ├── history_screen.dart
│   └── settings_screen.dart
└── widgets/                 # Reusable components
    ├── calculator_button.dart
    └── calculator_display.dart

🏗️ Build & Deployment

Android Signing Configuration

The project includes pre-configured Android signing for release builds:

1. Keystore Location: android/app/upload-keystore.jks
2. Signing Properties: android/app/signing.properties (gitignored for security)
3. Configuration: Automatically loaded in android/app/build.gradle.kts

Setting up Signing for Release

The signing configuration is already set up. For custom keystores:

1. Generate new keystore:

   cd android/app
   keytool -genkey -v -keystore your-keystore.jks -keyalg RSA -keysize 2048 -validity 10000 -alias your-alias

2. Update signing.properties:

   storeFile=your-keystore.jks
   storePassword=your-store-password
   keyAlias=your-alias
   keyPassword=your-key-password

3. Update build.gradle.kts if needed (already configured)

Build Commands

# Debug builds
flutter build apk                    # Android APK (debug)
flutter build ios --debug           # iOS (debug)
flutter build web                   # Web (debug)

# Release builds
flutter build apk --release         # Android APK (signed)
flutter build appbundle --release   # Android App Bundle (recommended)
flutter build ios --release         # iOS (signed)
flutter build web --release         # Web (production)

# Platform-specific
flutter build windows --release     # Windows
flutter build macos --release       # macOS
flutter build linux --release       # Linux

Deployment

Google Play Store

1. Build App Bundle:

   flutter build appbundle --release

2. Upload to Play Console:

   • Go to Google Play Console
   • Create new release
   • Upload build/app/outputs/bundle/release/app-release.aab

3. Configure Play Integrity (already integrated):

   • Enable API in Google Cloud Console
   • Configure integrity tokens in Play Console

Apple App Store

1. Build for iOS:

   flutter build ios --release

2. Archive in Xcode:

   • Open ios/Runner.xcworkspace
   • Product → Archive
   • Upload to App Store Connect

Web Deployment

1. Build web:

   flutter build web --release

2. Deploy to hosting:

   firebase deploy --only hosting
   # or upload build/web contents to your web server

Usage in Code

import 'package:calculator/play_integrity_service.dart';

// Check device integrity
bool isTrustworthy = await PlayIntegrityService.isDeviceTrustworthy();

// Get detailed integrity information
String details = await PlayIntegrityService.getIntegrityDetails();

Security Benefits

• Device Integrity: Detects rooted/jailbroken devices
• App Recognition: Verifies app authenticity
• Fraud Prevention: Protects against unauthorized modifications
• Compliance: Helps meet security requirements

🎨 App Logo & Icons

Current Logo Configuration

The app uses flutter_launcher_icons to generate launcher icons for all platforms from a single source image. The current configuration in pubspec.yaml:

flutter_launcher_icons:
  android: "launcher_icon"
  ios: true
  image_path: "assets/images/logo.png"
  min_sdk_android: 21
  web:
    generate: true
    image_path: "assets/images/logo-web.png"
    background_color: "#ffffff"
    theme_color: "#ffffff"
  windows:
    generate: true
    image_path: "assets/images/logo.ico"
    icon_size: 48
  macos:
    generate: true
    image_path: "assets/images/logo.png"

Required Logo Files

Place the following files in the assets/images/ directory:

• Android & iOS: logo.png (1024x1024px recommended)
• Web: logo-web.png (512x512px recommended, can be transparent)
• Windows: logo.ico (48x48px or larger, ICO format)
• macOS: logo.png (same as Android/iOS, PNG format)

How to Update the Logo

1. Replace the logo files in assets/images/ with your new logo files
2. Update file paths in pubspec.yaml if filenames change
3. Regenerate icons by running:

   dart run flutter_launcher_icons

Platform-Specific Details

Android

• Generates multiple icon sizes (hdpi, mdpi, xhdpi, xxhdpi, xxxhdpi)
• Creates ic_launcher.png and launcher_icon.png in each density folder
• Minimum SDK: API 21 (Android 5.0)

iOS

• Generates 20+ different icon sizes for all Apple devices
• Creates icons from 20x20px to 1024x1024px
• Updates Contents.json in the asset catalog

Web (PWA)

• Generates Icon-192.png, Icon-512.png for PWA
• Creates Icon-maskable-192.png, Icon-maskable-512.png for adaptive icons
• Updates manifest.json with icon references
• Sets background and theme colors

Windows

• Generates app_icon.ico in the Windows runner resources
• Icon size: 48x48px (configurable)
• Used for desktop shortcuts and taskbar

macOS

• Generates multiple PNG sizes from 16x16px to 1024x1024px
• Creates icons for dock, menu bar, and system preferences
• Updates Contents.json in the macOS asset catalog

Tips for Best Results

• Use PNG format for transparency support
• Ensure logos have sufficient padding (at least 10% margin)
• Test on actual devices after generation
• For iOS, avoid pure white logos (use a colored background)
• For web, consider both masked and unmasked versions

🧪 Testing

Running Tests

# Run all tests
flutter test

# Run tests with coverage
flutter test --coverage

# Run specific test file
flutter test test/calculator_provider_test.dart

# Run tests in watch mode (re-runs on file changes)
flutter test --watch

# Run integration tests
flutter test integration_test/

Test Coverage

# Generate coverage report
flutter test --coverage

# View coverage report (requires lcov)
genhtml coverage/lcov.info -o coverage/html
open coverage/html/index.html

Code Quality

# Analyze code for issues
flutter analyze

# Format code
dart format .

# Check for unused files
flutter pub run dart_code_metrics:metrics check-unused-files lib

# Run all quality checks
flutter analyze && flutter test

🔧 Troubleshooting

Common Issues

Build Issues

Android Build Fails

# Clean and rebuild
flutter clean
flutter pub get
flutter build apk --debug

# Check Java version
java -version

# Accept Android licenses
flutter doctor --android-licenses

iOS Build Fails

# Clean iOS build
cd ios && rm -rf Pods/ Podfile.lock && cd ..
flutter clean
flutter pub get
cd ios && pod install && cd ..
flutter build ios

Firebase Configuration Issues

# Check Firebase config files exist
ls android/app/google-services.json
ls ios/Runner/GoogleService-Info.plist

# Re-download Firebase config if missing
# Go to Firebase Console → Project Settings → Your apps

Runtime Issues

App Crashes on Startup

• Check device logs: flutter logs
• Verify Firebase configuration
• Check for missing permissions
• Ensure minimum SDK requirements are met

Calculation Errors

• Check expression syntax
• Verify mathematical operations are supported
• Review error logs in debug console

Database Issues

• Clear app data to reset local database
• Check available storage space
• Verify database file permissions

Debug Commands

# View device logs
flutter logs

# Run in verbose mode
flutter run --verbose

# Check Flutter doctor
flutter doctor -v

# Clean all build artifacts
flutter clean
rm -rf pubspec.lock
flutter pub get

Performance Issues

• Slow startup: Check Firebase initialization
• UI lag: Profile with Flutter DevTools
• Memory issues: Monitor with Android Profiler/iOS Instruments
• Battery drain: Check background services

📊 Project Metrics

Code Quality

• Test Coverage: Target >80%
• Code Analysis: Zero flutter analyze warnings
• Platform Support: 6 platforms (Android, iOS, Web, Windows, macOS, Linux)

Performance

• Startup Time: <2 seconds (cold start)
• Memory Usage: <50MB (average)
• Battery Impact: Minimal background usage
• Smooth Animations: 60 FPS target

Security

• Code Obfuscation: Enabled in release builds
• Certificate Pinning: Firebase security
• Play Integrity: Device verification
• Secure Storage: Encrypted local data

📱 Platform Support

• ✅ Android (API 21+)
• ✅ iOS (iOS 12+)
• ✅ Windows (Windows 10+)
• ✅ macOS (macOS 10.14+)
• ✅ Linux (Ubuntu 18.04+)
• ✅ Web (Chrome, Firefox, Safari)

🤝 Contributing

We welcome contributions! Please see our Contributing Guidelines for details.

Development Setup

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit your changes: git commit -m 'Add amazing feature'
4. Push to the branch: git push origin feature/amazing-feature
5. Open a Pull Request

Code Style

• Follow Dart and Flutter conventions
• Use flutter analyze to check for issues
• Format code with dart format
• Write tests for new features

📄 License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

📞 Support

If you found this project helpful, please consider:

• ⭐ Starring the repository
• 🐛 Reporting bugs
• 💡 Suggesting new features
• 🤝 Contributing to the code

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Made with ❤️ using Flutter