Technical guide

FleetTax Docs

A practical reference for the offline Android app: architecture, data flow, notification behavior, setup, build steps, and release resources.

Product

What FleetTax does

FleetTax helps Indian bus and truck fleet owners track Vahan road tax deadlines without depending on cloud sync. Operators can add vehicles, choose the tax period, view the calculated expiry state, receive local reminders, open the Vahan portal, and record payment references after renewal.

01 Offline records

SQLite keeps vehicle data on the device for fast access.

02 Expiry logic

Monthly, quarterly, and yearly periods calculate status automatically.

03 Payment loop

Open Vahan, pay tax, then log date, period, and receipt reference.

Architecture

Application structure

The app follows a clear Flutter structure: models hold business rules, the database helper owns persistence, services handle platform concerns, providers coordinate state, and screens/widgets render the user workflow.

lib/
  main.dart
  models/vehicle.dart
  db/database_helper.dart
  providers/vehicle_provider.dart
  services/notification_service.dart
  screens/dashboard_screen.dart
  screens/add_edit_screen.dart
  screens/mark_paid_screen.dart
  widgets/vehicle_card.dart
  widgets/stats_bar.dart
  widgets/filter_chips.dart

Vehicle input Provider state SQLite storage Status dashboard

Persistence

Vehicle data model

Field	Purpose	Example
`reg`	Vehicle registration number	`DL01AB1234`
`type`	Commercial vehicle class	`bus` or `truck`
`taxPeriod`	Validity period for the most recent payment	`monthly`, `quarterly`, `yearly`
`lastPaid`	Payment date used to calculate expiry	`2026-05-15`
`receiptRef`	Optional receipt or transaction reference	`VAHAN-2026-001`

Reminders

Notification behavior

FleetTax uses WorkManager for periodic background checks and flutter_local_notifications for local alerts. Vehicles become attention-worthy when they are expired or within the 10-day warning window.

Load saved vehicles from SQLite.
Calculate each expiry date from lastPaid + taxPeriod.
Classify status as expired, due soon, or valid.
Show local notifications for expired and due-soon vehicles.

Developer setup

Run locally

flutter pub get
flutter analyze
flutter test
flutter run

The project targets Flutter with Dart SDK 3.11.5 or newer and Android 13+ behavior for notifications. Keep emulator or device notification permissions enabled while validating reminders.

Release

Build and distribute

flutter clean
flutter pub get
flutter build apk --release

APK output

build/app/outputs/flutter-apk/app-release.apk

Public release

Attach the APK and PDF guide to the GitHub Releases page.

Support

Troubleshooting checklist

Notifications do not appear

Grant notification permission, verify WorkManager setup, and test on a real device when possible.

Database data looks stale

Hot restart the app, inspect SQLite migrations, and verify provider reload calls after writes.

Vahan link does not open

Run on a device with a browser installed and check url_launcher Android configuration.