A comprehensive Flutter application for Bluetooth Low Energy (BLE) device scanning, connection, and interaction with Material 3 design principles.

• Flutter SDK (3.0.0 or later)
• Dart SDK (2.19.0 or later)
• Android Studio / Xcode for device deployment
• Physical device with Bluetooth capabilities (BLE scanning requires hardware)

1. Clone the Repository

   git clone https://github.com/ogaroh/smart-ble.git
   cd smart_ble

2. Install Dependencies

   flutter pub get

3. Configure Flavors The app supports multiple build flavors:

   • dev - Development environment
   • stag - Staging environment
   • prod - Production environment

4. Run the Application

   Development Mode:

   flutter run --flavor dev --target lib/main_dev.dart

   Production Mode:

   flutter run --flavor prod --target lib/main_prod.dart

   Build APK:

   flutter build apk --flavor prod --release --target lib/main_prod.dart

   Build Appbundle (Play Store Release):

   flutter build appbundle --flavor prod --release --target lib/main_prod.dart

• Minimum SDK: 21 (Android 5.0)
• Target SDK: 34
• Permissions automatically handled: BLUETOOTH, BLUETOOTH_ADMIN, ACCESS_FINE_LOCATION

• iOS 12.0 or later
• Bluetooth permissions handled via Info.plist

• Physical Device Required: BLE functionality requires a physical device with Bluetooth capabilities
• Location Permission: Android requires location permission for BLE scanning
• Bluetooth Must Be Enabled: Ensure Bluetooth is enabled on the device before running

Why BLoC was chosen:

1. Separation of Concerns: Clear separation between UI, business logic, and data layers
2. Testability: Easy to unit test business logic independent of UI
3. Scalability: Excellent for complex applications with multiple screens and states
4. Reactive Programming: Stream-based use-case perfect for BLE connection state management
5. Ecosystem: Excellent support from the community in general

├── Core Layer
│   ├── Models (BLE data structures)
│   ├── Theme (Material 3 styling)
│   └── Repository (BLE operations)
├── Feature Layer
│   ├── Device Scanner (BlocProvider + BlocBuilder)
│   └── Device Details (BlocProvider + BlocConsumer)
│   └── Settings (BlocProvider + BlocConsumer)
└── Presentation Layer
    ├── Screens (StatelessWidgets)
    └── Widgets (Reusable components)

Key BLoC Components:

• DeviceScannerBloc: Manages BLE scanning, device discovery, and filtering
• DeviceDetailBloc: Handles device connection, service discovery, and characteristic operations
• SettingsBloc: Theme changes, Bluetooth timeout settings, Scanning preferences & other advanced settings (granular) that might be implemented later
• Events: User actions (scan, connect, read characteristics)
• States: UI states (loading, loaded, error, connecting, etc.)

State Flow Example:

User clicks "Connect" → ConnectToDeviceEvent →
DeviceDetailConnecting (immediate UI feedback) →
BLE Connection → DeviceDetailConnected →
Auto Service Discovery → DeviceDetailDiscoveringServices →
Services Found → DeviceDetailConnected (with services)

• Challenge: BLE connection states can change rapidly and unpredictably
• Solution: Implemented immediate UI feedback with state-specific classes (DeviceDetailConnecting, DeviceDetailConnected, etc.)

• Challenge: BLE scanning can be inconsistent, especially on different devices
• Solution: Added robust error handling, scan timeouts, and user feedback for scanning issues

• Challenge: Not all devices expose manufacturer information via standard characteristics
• Solution: Graceful fallback with proper error states (unavailable, loading, error, available)

• Challenge: Ensuring consistent theming across complex UI components
• Solution: Custom theme system with AppColors class and comprehensive styling

• Challenge: Supporting dev/staging/production environments
• Solution: Implemented flavorizr configuration with separate main entry points

• Assumed target devices have Bluetooth 4.0+ BLE support
• Assumed users will grant necessary permissions when prompted
• Assumed physical device testing (emulator limitations acknowledged)

• Users prefer immediate visual feedback over waiting for actual BLE responses
• Device connection attempts should have reasonable timeouts
• Error messages should be user-friendly rather than technical

• Standard BLE service UUIDs (Device Information: 180A, Battery: 180F)
• Common characteristic UUIDs for manufacturer name (2A29), model number (2A24)
• UTF-8 encoding for readable characteristic values

• Device lists under 50 items perform adequately without any lag
• Service discovery is fast enough for auto-triggering on connection
• Memory usage acceptable for typical BLE device discovery & communication sessions

• Implementation: Full Material 3 design system with dynamic theming & custom settings
• Features:
  • Added an extra Settings module
  • Custom color schemes and typography
  • Smooth animations and transitions
  • Consistent iconography and spacing
  • Responsive layout design
  • full localization support for 4 languages (English, Swahili, French & Spanish). The language conforms to the system language

• Implementation: Automatic manufacturer name detection via the Device Information Service (0x180A)
• Features:
  • Auto-discovery of manufacturer name characteristic (0x2A29)
  • Loading states with progress indicators
  • Error handling for unsupported devices
  • Graceful fallback for unavailable information

• Dev, Staging, and Production flavors
• Environment-specific configurations
• Separate app icons and names per flavor

• Network-aware error messages
• User-friendly error states
• Recovery suggestions and actions

• Service and characteristic discovery
• Real-time connection state monitoring
• RSSI signal strength display
• Characteristic property analysis (Read, Write, Notify, etc.)

• Comprehensive code documentation
• Error boundary implementations
• Proper resource cleanup (connection disposal)
• Memory leak prevention etc.

Download Smart BLE APK Production build with release optimizations

Watch Application Demo Complete walkthrough of BLE scanning, connection, and service discovery

• Flutter Version: 3.24.5

• Dart Version: 3.5.4

• Key Dependencies:

  • flutter_blue_plus: ^1.36.8 (BLE functionality)
  • flutter_bloc: ^8.1.6 (State management)
  • permission_handler: ^11.4.0 (Runtime permissions)
  • equatable: ^2.0.5 (Value equality)

• Supported Platforms: Android (API 21+), iOS (12.0+)

• Architecture: Clean Architecture with BLoC pattern

• Design System: Material 3 with custom theming

This Smart BLE application demonstrates a production-ready Flutter implementation with modern architecture patterns, comprehensive error handling, and user-centric design. The BLoC pattern provides excellent separation of concerns and maintainability, while the Material 3 design ensures a polished user experience across different devices and screen sizes.

The implementation successfully addresses all core requirements while adding significant value through bonus features and robust engineering practices.