AMA-POS

A simple Android tablet-first Point of Sale (POS) system built with Flutter.

Package name: tw.kazan.amapos

Features

Cashier (櫃台)

• Create orders: add/remove items, adjust quantities
• Switch between dine-in (內用) and takeout (外帶), with table number for dine-in
• Quick cash checkout: shows amount due, enter received amount, displays change
• Support for "add items after sub-total": navigate back from checkout to add more items

Backoffice (商家後台)

• Category management (CRUD + enable/disable)
• Product management (CRUD + enable/disable)
• Shift management: open/close shifts with statistics
• Daily reports: view daily sales by date
• Import/Export: JSON config file for merchant settings, categories, and products

Tech Stack

• Flutter (3.x)
• Riverpod (state management, plain providers — no code generation)
• go_router (navigation)
• sqflite (SQLite local database, no code generation needed)
• file_picker + path_provider (file import/export)
• intl (formatting)
• uuid (ID generation)

Project Structure

lib/
  app/             # app.dart, router.dart, theme.dart
  core/
    db/            # AppDatabase (sqflite), models, dao stubs
    utils/         # money, datetime, id helpers
  features/
    cashier/       # Cashier feature (pages, widgets, state, repo)
    backoffice/    # Backoffice feature (pages, state, repo)
android/           # Android-specific configuration

Getting Started

Prerequisites

• Flutter SDK >= 3.10.0
• Android SDK with API 21+
• Android tablet or emulator (landscape orientation recommended)

Setup

# Install dependencies
flutter pub get

# Run on Android
flutter run

No code generation required. This project uses sqflite for the database and plain Riverpod providers, so build_runner is not needed.

First Run

The app automatically seeds sample data on first launch:

• Categories: 飲料 (drinks), 餐點 (food), 小食 (snacks)
• 12 sample products across the categories

Architecture

• Feature-first folder structure
• Riverpod StreamProvider / Provider for dependency injection and reactive state
• sqflite for all persistent storage with polling-based reactive streams
• Repository pattern for data access isolation
• go_router for declarative navigation

Database Schema

Table	Description
categories	Product categories with sort order and active flag
products	Products with price (in NT$), category, sort order
orders	Sales orders with type (dineIn/takeOut), status, totals
orderItems	Line items with name/price snapshots
payments	Payment records (cash)
shifts	Cashier shifts with open/close times and cash amounts
merchantConfigs	Single-row merchant settings

MVP Scope

• Offline-only, single device
• Cash payments only (no payment gateway)
• No receipt printing (can be added later)
• Import/Export does not include order history or images

Android Configuration

• applicationId: tw.kazan.amapos
• minSdk: 21
• targetSdk: 34
• compileSdk: 34
• Orientation: Landscape (tablet-optimised layout)