RentalWheels

A modern Android car rental simulation app built with Jetpack Compose and Firebase. This is a portfolio project demonstrating clean architecture, reactive programming, and modern Android development practices.

Note: This is a demonstration app. Booking functionality is simulated and no real transactions occur.

Screenshots

<table> <tr> <td><img src="screenshots/settings_dark.png" width="200"/></td> <td><img src="screenshots/bookings_available_cars.png" width="200"/></td> <td><img src="screenshots/browse_cars.png" width="200"/></td> </tr> <tr> <td><img src="screenshots/home_screen.png" width="200"/></td> <td><img src="screenshots/car_details.png" width="200"/></td> <td><img src="screenshots/filters.png" width="200"/></td> </tr> </table>

Features

• Browse cars with filtering (brand, year, fuel type, transmission, price)
• Simulated booking flow with cart functionality
• User authentication via Firebase
• Theme customization (Light/Dark/System)
• Real-time data synchronization with Firestore
• Booking history and analytics

Tech Stack

Core

• Kotlin - Primary language
• Jetpack Compose - Declarative UI framework
• Material Design 3 - UI components and theming
• Coroutines & Flow - Asynchronous programming

Architecture

• MVVM - Separation of concerns with ViewModels
• Repository Pattern - Data layer abstraction
• Hilt - Dependency injection
• Navigation Compose - Type-safe navigation

Firebase

• Firestore - NoSQL database for car data
• Authentication - Email/password authentication
• Storage - Car images

Libraries

• Coil - Image loading
• Accompanist - System UI controller
• Material Icons Extended - Icon library

Architecture

The app follows MVVM architecture with clear separation of concerns:

┌─────────────────────────────────────┐
│         UI Layer (Compose)          │
│  Screens + Reusable Components      │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│         ViewModel Layer             │
│  State Management + Business Logic  │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│        Repository Layer             │
│    Data Access Abstraction          │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│         Firebase Backend            │
│  Firestore + Auth + Storage         │
└─────────────────────────────────────┘

Key Components

ViewModels

• CarViewModel - Manages car catalog and home screen state
• BookingsViewModel - Handles booking operations and cart state
• BrowseViewModel - Controls filtering and search
• AnalyticsViewModel - Processes booking statistics

Repositories

• CarRepository - Fetches and caches car data from Firestore
• BookingRepository - Manages booking lifecycle

Design System

• Custom spacing scale (4dp to 64dp)
• Material 3 color system with theme support
• Consistent elevation and typography

Data Flow

1. User interacts with Composable UI
2. ViewModel processes business logic
3. Repository fetches/updates data from Firebase
4. StateFlow emits new state
5. UI recomposes with updated data

Setup

Prerequisites

• Android Studio Hedgehog or later
• JDK 17+
• Android SDK (minSdk 24, targetSdk 34)

Installation

1. Clone the repository

git clone https://github.com/muchaisam/Rentalwheels.git

2. Add google-services.json to app/ directory

3. Build and run

./gradlew assembleDebug

Firebase Configuration

Create a Firebase project and enable:

• Authentication (Email/Password)
• Firestore Database
• Storage

The app expects the following Firestore structure:

cars/
  {carId}/
    - name: String
    - brand: String
    - model: String
    - year: Int
    - dailyRate: Int
    - imageUrl: String
    - category: String
    - transmission: String
    - fuelType: String
    - seats: Int
    - features: List<String>

Project Structure

app/src/main/java/com/msdc/rentalwheels/
├── data/
│   ├── model/              # Data classes
│   └── repository/         # Data access layer
├── ui/
│   ├── components/         # Reusable composables
│   ├── screens/            # Screen-level composables
│   └── theme/              # Design system & theming
├── viewmodel/              # ViewModels
└── utils/                  # Utility classes

Implementation Highlights

Reactive Theme System

• Theme changes update system UI instantly without restart
• SharedPreferences listener triggers recomposition
• Supports Light, Dark, and System themes

Efficient Image Loading

• Coil handles async loading with memory/disk caching
• Crossfade animations for smooth transitions

State Management

• StateFlow for reactive UI updates
• ViewModel survives configuration changes
• Clean separation between business logic and UI

Firebase Integration

• Real-time data sync with Firestore
• Optimistic UI updates with local caching
• Proper error handling and loading states

License

MIT License - see LICENSE for details

Contact

Samson Muchai

• Email: sam1muchai@gmail.com
• GitHub: @muchaisam
• Twitter: @smuchai10