jetpacker

JetPacker

Home Screen	Trip Itinerary	Flight Detail

Overview

JetPacker provides users with powerful tools to manage their upcoming trips, build out rich itineraries, record voice notes, manage travel expenses, generate on-device "Trip Summaries and Tips", generate AI reviews, chat with hotel staff via automatic translation, get real-time museum assistant guidance, and contribute to Android's intelligence system with trip management functions through AppFunctions.

Architecture

This project is built using modern Android architecture components:

• UI: Jetpack Compose
• Dependency Injection: Dagger/Hilt
• Local Persistence: Room Database
• State Management: ViewModels with StateFlow
• On-Device AI: ML Kit GenAI (Prompt, Speech Recognition, Translation)
• Cloud & Hybrid AI: Firebase AI Logic (Gemini grounded with URL/Maps/Search, and hybrid models with on-device fallback)
• App Security: Firebase App Check (with Play Integrity and Debug Provider)
• Assistant Integration: Android AppFunctions (androidx.appfunctions)

Module Overview

JetPacker follows a clean, multi-module Android structure organized by responsibility and domain:

Core Modules (:core:*)

• :core:ui: Shared Jetpack Compose design system components (JetPackerFab, JetPackerToolbar, themes, custom typography).
• :core:flags: Centralized feature toggle system (FeatureFlags) controlling optional runtime capabilities.
• :core:speech: On-device speech recognition wrappers and audio processing utilities.

Data Modules (:data:*)

• :data:db: Room database configuration, entities, and local DAOs.
• :data:trips: Repository layer and data models managing high-level trip records.
• :data:itinerary: Repository layer and data models managing daily itinerary events (TimelineEvent, EventType).

Feature Modules (:feature:*)

• :feature:home: Dashboard screen displaying the user's upcoming trips list.
• :feature:create_trip: Unified trip form module handling both new trip creation and existing trip editing (EditTripScreen).
• :feature:detail: Detailed view screens for specific itinerary events (Flights, Hotels, Restaurants, Museums, Tours).
• :feature:appfunctions: Android AppFunctions framework integration (JetPackerAppFunctionService) contributing structured functions to Android's intelligence system for trips, expenses, itineraries, and voice notes.
• :feature:trip: Top-level trip container shell (TripScreen) holding bottom navigation and orchestrating trip sub-tabs.
  • :feature:trip:itinerary: Pure itinerary timeline screen displaying daily scheduled events.
    • :feature:trip:itinerary:enrichment: On-device AI summaries and tips (TripSummaryAndTipsCard) and dynamic daily theme generators.
  • :feature:trip:expenses: Expense tracking screen and automated receipt parser.
  • :feature:trip:voice_notes: Audio voice note recorder and real-time speech-to-text transcription screen.

Getting Started

This project is built using the standard Android Gradle build system, allowing developers to quickly build, run, and experiment with the application locally using Android Studio.

Configuration Setup

1. Local Properties Setup:

   • Navigate to the android directory and copy local.properties.example to local.properties:

     cd android
     cp local.properties.example local.properties

   • Update sdk.dir inside local.properties with your local Android SDK directory path.

2. Firebase Setup (google-services.json):

   • Register the application in your Firebase Project Console.
   • Download the project's custom google-services.json and place it in the android/app/ directory (overwriting the mock placeholder file).

3. Firebase App Check Debug Attestation:

   • Run the application on an emulator or a connected device.
   • Filter your logcat logs for DebugAppCheckProvider. You will see a log similar to:

     Enter this debug secret into the allow list in the Firebase Console for your project: a8c2dd4c-7f7f-4764-b653-ef6c114ba27e
     

   • Copy the debug token and register it in the Firebase Console under App Check -> Apps -> Manage Debug Tokens.

Building Using Gradle

To compile the application and run unit tests using Gradle, execute the following commands in your terminal (from the android directory):

# Navigate to the android directory
cd android

# Build a debug APK
./gradlew :app:assembleDebug

# Run unit tests
./gradlew test

On-Device AI Features

JetPacker integrates local on-device AI capabilities using ML Kit. These features run entirely on-device and can be toggled or customized in android/core/flags/src/main/kotlin/com/example/jetpacker/core/flags/FeatureFlags.kt:

• ENABLE_TRIP_SUMMARY_AND_TIPS: Generates an on-device card summary of the current trip using ML Kit GenAI Prompt.
• ENABLE_ITINERARY_ENRICHMENT: Local enrichment for timeline events.
• ENABLE_EXPENSE_MANAGEMENT: Local expense management receipt scanner and parser.
• ENABLE_VOICE_NOTES: On-device speech recognition and transcription for voice notes.

Cloud-Hybrid & Online AI Features

JetPacker also integrates online hybrid features using Firebase AI Logic (Gemini API) and ML Kit:

• ENABLE_MUSEUM_ASSISTANT: Museum Assistant chatbot with URL, Maps, and Search grounding (uses Gemini 3.5 flash-lite).
• ENABLE_REVIEW_GENERATION: Topic-selected review generator (uses Gemini 3.5 flash-lite on-device with cloud fallback).
• Hotel Support Chat: Receives hotel receptionist assistance with real-time ML Kit + Gemini translation.

AppFunctions Integration

JetPacker uses Android's AppFunctions library (androidx.appfunctions) in :feature:appfunctions to contribute to Android's intelligence system with structured travel actions and data queries via JetPackerAppFunctionService:

• Trip Management: searchTrip (filter by ID, name, location, and dates) and createTrip.
• Itinerary Events: getItinerary and addItineraryEvent (activity, dining, accommodation, etc.).
• Expense Tracking: getExpenses and addExpense (amount, currency, category).
• Voice Notes: getVoiceNotes and addVoiceNote (recorded transcriptions linked to trips).
• Day Themes: getDayThemes and setDayTheme for daily trip customization.

IDE Setup & Development

To work on JetPacker locally, open the project in Android Studio:

1. Open Android Studio and select Open an Existing Project (or File > Open).
2. Select the android directory folder within the repository.
3. Android Studio will automatically sync Gradle and prepare the project.