CrimeLink Analyzer Mobile App

React Native + Expo mobile client for the CrimeLink Analyzer platform.

This app connects to:

• CrimeLink backend APIs (authentication, duty, leave, announcements, safety zones, weapon requests, officer location)
• Firebase (chat/auth-related integrations)
• Google Maps services (map and location features)

Tech stack

• Expo SDK 54
• React Native 0.81
• Expo Router (file-based routing)
• TypeScript
• NativeWind
• Axios
• Firebase

Prerequisites

Install the following before running:

• Node.js 18+ (recommended: latest LTS)
• npm 9+
• Expo CLI (via npx, no global install required)
• Android Studio (for Android emulator) or Xcode (for iOS simulator on macOS)

For API calls to work, run the backend service and make sure its URL is reachable from your device/emulator.

Environment configuration

This project reads environment values from:

• .env.development
• .env.preview
• .env.production

The selected file depends on APP_ENV (default is development).

1. Create your env file

From this folder, copy .env.example to one of the environment files:

cp .env.example .env.development

2. Fill required values

At minimum, set all of the following keys:

API_URL=
FIREBASE_API_KEY=
FIREBASE_AUTH_DOMAIN=
FIREBASE_PROJECT_ID=
FIREBASE_STORAGE_BUCKET=
FIREBASE_MESSAGING_SENDER_ID=
FIREBASE_APP_ID=

Optional but recommended:

GOOGLE_MAPS_API_KEY=

API_URL tips

• Android emulator (calling backend on your machine):

API_URL=http://10.0.2.2:8080

• iOS simulator:

API_URL=http://localhost:8080

• Physical device (same Wi-Fi as your machine):

API_URL=http://<YOUR_LOCAL_IP>:8080

Install dependencies

npm install

Run the app

Start Expo dev server

Development environment (default):

npx expo start

Use a specific environment file:

APP_ENV=preview npx expo start
APP_ENV=production npx expo start

Run on Android

npm run android

Run on iOS (macOS only)

npm run ios

Run on web

npm run web

Lint

npm run lint

Typical local workflow

1. Start backend service (default expected port: 8080).
2. Configure .env.development with valid API/Firebase values.
3. Install dependencies with npm install.
4. Start Expo using npx expo start.
5. Launch on emulator/device (a for Android, i for iOS in Expo terminal, or use npm scripts).

Build and deployment notes

• App config values are injected through app.config.js into Expo extra.
• If you use EAS Build, define the same env vars in your EAS environment. Missing values can cause runtime failures when reading config.

Project structure

• app/ route screens (Expo Router)
• src/api/ API client setup
• src/services/ feature service layers
• src/constants/ shared constants and runtime config
• src/components/ reusable UI and feature components
• src/context/ and src/hooks/ app state and hooks

Troubleshooting

• Error: Missing required app config
  • Check .env.* values and confirm you started the app with the intended APP_ENV.
• Network request failed
  • Verify backend is running and API_URL is reachable from emulator/device.
• Android physical device cannot reach backend
  • Use your machine local IP address, not localhost.

Useful scripts

• npx expo start - Start Expo development server
• npm run android - Build/run on Android
• npm run ios - Build/run on iOS
• npm run web - Run web target
• npm run lint - Lint project
• npm run reset-project - Reset scaffolded starter structure