Android Architecture

Android Architecture

Overview

RunOn! follows Clean Architecture principles with MVVM (Model-View-ViewModel) pattern for the presentation layer. This ensures separation of concerns, testability, and maintainability.

Architecture Layers

1. Presentation Layer (UI)

Components

• Activities/Composables: UI containers and navigation hosts
• Compose UI: Declarative UI components
• ViewModels: UI state management and business logic
• UI State: Immutable state objects
• UI Events: User interactions and UI events

Key Patterns

• Unidirectional Data Flow: State flows down, events flow up
• State Hoisting: State management pattern for Compose
• Screen-based Architecture: Each major feature is a separate screen module

2. Domain Layer

Components

• Use Cases: Business logic operations
• Domain Models: Core business objects
• Repository Interfaces: Data access contracts
• Domain Events: Business event definitions

Key Patterns

• Clean Architecture: Separation of domain logic
• Single Responsibility: Each use case handles one operation
• Dependency Inversion: Domain layer defines interfaces

3. Data Layer

Components

• Repositories: Data access implementation
• Data Sources: Remote and local data providers
• DTOs: Data transfer objects
• Mappers: Object transformations

Key Patterns

• Repository Pattern: Single source of truth
• Offline First: Local cache as primary data source
• Data Mapping: Clear separation between data and domain models

Module Structure

app/
├── core/
│   ├── common/           # Shared utilities and extensions
│   ├── design/           # Design system and UI components
│   ├── navigation/       # Navigation components
│   └── testing/          # Test utilities and fakes
├── data/
│   ├── remote/           # API and remote data sources
│   ├── local/            # Room database and local storage
│   └── repository/       # Repository implementations
├── domain/
│   ├── model/           # Domain models
│   ├── repository/      # Repository interfaces
│   └── usecase/         # Business logic use cases
└── features/
    ├── events/          # Event discovery feature
    ├── calendar/        # Calendar integration
    ├── social/          # Social features
    └── profile/         # User profile management

Key Architectural Decisions

1. Dependency Injection

• Hilt for dependency injection
• Module-level component provision
• Scoped dependencies for efficient resource usage

2. Navigation

• Navigation Compose for screen navigation
• Deep linking support
• Type-safe navigation arguments

3. State Management

data class EventsUiState(
    val events: List<Event> = emptyList(),
    val isLoading: Boolean = false,
    val error: String? = null
)

sealed interface EventsUiEvent {
    data class OnEventSelected(val eventId: String) : EventsUiEvent
    object OnRefreshRequested : EventsUiEvent
    // ... other events
}

4. Error Handling

• Centralized error handling
• Error mapping to UI states
• Consistent error presentation

5. Testing Strategy

• Unit Tests: Domain and ViewModel logic
• Integration Tests: Repository and data layer
• UI Tests: Critical user flows
• Screenshot Tests: UI components

Data Flow

1. UI Layer:

   • Composables observe ViewModel state
   • User actions trigger UI events
   • ViewModels process events

2. Domain Layer:

   • Use cases execute business logic
   • Repository interfaces define data contracts
   • Domain models represent business objects

3. Data Layer:

   • Repositories coordinate data sources
   • Data sources handle raw data
   • Mappers transform between layers

Security Considerations

• Data Encryption: Sensitive data encryption at rest
• Network Security: SSL pinning and secure communication
• Authentication: AWS Cognito integration
• Authorization: Role-based access control

Performance Optimization

• Lazy Loading: On-demand resource loading
• Caching: Multi-level caching strategy
• Background Processing: WorkManager for background tasks
• Memory Management: Lifecycle-aware components

Monitoring and Analytics

• Crash Reporting: Crashlytics integration
• Performance Monitoring: Firebase Performance
• Analytics: User behavior tracking
• Logging: Structured logging strategy

Future Considerations

• Modularization: Further module separation
• Dynamic Features: On-demand feature delivery
• Compose Multiplatform: Potential iOS support
• Backend-Driven UI: Server-driven UI components