GroceryCheckList

A real-time, cross-platform grocery list application designed for Android (Phone) and watchOS (Standalone Apple Watch).

This app allows you to manage your grocery list on your phone and check items off directly from your wrist while at the store, even without your phone nearby.

Architecture

This project uses a unique Hybrid Architecture to support true standalone functionality on Apple Watch while maintaining a robust Android experience.

Backend

• Firebase Firestore: Central database acting as the single source of truth.
• Data Model:
  • groceries collection.
  • Fields: name (string), isCompleted (boolean), order (int), createdAt (timestamp).

Android App

• Tech Stack: Kotlin, Jetpack Compose, Firebase Android SDK.
• Sync: Uses standard real-time listeners (SnapshotListener) from the Firebase SDK for instant updates.
• Features: Add, delete, reorder, and complete items.

Apple Watch App

• Tech Stack: Swift, SwiftUI.
• Sync: Uses Firestore REST API via URLSession.
  • Why? Official Firebase SDK support for standalone watchOS is limited. Using REST ensures the app can run independently over Wi-Fi/LTE without complex linking errors.
• Sync Strategy:
  • Fetches data on launch.
  • Polls for updates every 10 seconds while in the foreground.
  • Optimistic UI updates for checking off items.

Setup Instructions

Prerequisites

1. Android Studio (for Android app).
2. Xcode 15+ (for Watch app).
3. Java 17 (required for Android build).

Firebase Configuration

Since configuration files are git-ignored for security, you must add your own:

1. Create a Firebase Project.
2. Android:
   • Register an Android app (com.example.grocery).
   • Download google-services.json and place it in android/app/.
3. watchOS:
   • Register an iOS app (JordanTranchina.GroceryWatch.watchkitapp).
   • Download GoogleService-Info.plist and place it in ios/GroceryWatch/.
4. Firestore:
   • Enable Firestore in the Firebase Console.
   • Start in Test Mode or configure rules to allow read/write.

Building

Android:

cd android
./gradlew assembleDebug

watchOS: Open ios/GroceryWatch/GroceryWatch.xcodeproj in Xcode and build for the "GroceryWatch Watch App" scheme.

Features

• ✅ Real-time Sync: Updates propagate between devices in seconds.
• ✅ Standalone Mode: Watch app works via Wi-Fi/LTE without the phone.
• ✅ Smart Sorting: Unchecked items float to the top; completed items sink to the bottom!