M-CommerceAndroidFull-Stack2024

Dees
Fashion

A full-stack Android M-Commerce platform transforming a traditional Sri Lankan clothing retailer into a digital-first business — biometric-secured checkout, offline-first architecture, and a real-time web admin dashboard.

Android

Platform

Spring Boot

Backend

3 Stores

Databases

PayHere

Payment

Tech Stack

Android StudioJavaSpring BootMySQLFirebaseRoom / SQLiteRetrofitOkHttpGoogle Maps APIPayHere SDKBiometricPromptCloudinaryFCMGson

Architecture

Android App

Java

Spring Boot API

:8080

MySQL

Transactions

also connects to

Firebase

Auth + Sync + FCM

·

Room / SQLite

Offline Cache

·

PayHere

Payments

→BiometricPrompt API intercepts checkout before any payment session is created — blocking unauthorized orders at the source.

→Room DAO serves as the primary read store. Firebase sync is opportunistic — app never degrades to a loading screen on network loss.

→Retrofit + OkHttp handle all API communication. FCM delivers personalised push notifications at each order lifecycle stage.

Features

Key Request Flows

1

Customer adds items to cart. Retrofit calls POST /cart/add — Spring Boot validates stock in MySQL before confirming each item.

2

Customer taps Checkout. BiometricPrompt API launches fingerprint / face ID dialogue before any payment intent is created.

3

Biometric success — app calls POST /checkout/initiate. Spring Boot creates a PayHere session and returns the hosted payment URL.

4

PayHere processes payment. On success callback, Spring Boot updates order status to CONFIRMED and triggers FCM notification.

5

PDF invoice generated server-side and pushed to device Downloads. Order appears in history with full tracking timeline.

Test Results

ID	Area	Test Case	Outcome	Status
TC_01	Security	Biometric prompt	Fingerprint prompt displayed on checkout	PASS
TC_02	Security	Unauthorized attempt	Access denied on wrong fingerprint	PASS
TC_03	Security	Authorized user	Payment proceeds after biometric success	PASS
TC_04	Reliability	Offline catalog	Catalog loads from SQLite with no network	PASS
TC_05	Reliability	Real-time sync	New product appears instantly on app	PASS
TC_06	Reliability	Search restriction	Search disabled offline with user prompt	PASS

Engineering Highlights

🔐

Multi-layer security

Three independent security checkpoints: OTP on registration, encrypted credentials in MySQL, and biometric gating before every payment — each layer independently blocking attack vectors.

📡

Offline-first architecture

Room/SQLite serves as the primary data store. Firebase sync is opportunistic — the app never degrades to a loading screen just because the network dropped.

💳

Biometric payment gate

BiometricPrompt API intercepts the checkout flow before any payment session is created, not after — preventing accidental orders and unauthorized use of saved payment methods.

📦

Polyglot data layer

MySQL for transactional order and user data, Firebase for real-time sync and push, Room for local caching, and Cloudinary for media — each store optimised for its access pattern.

📍

GPS-to-store routing

Directions API integration provides turn-by-turn routing from the customer's live GPS position to the nearest physical branch — bridging digital browsing with in-store pickup.

🧾

Server-side PDF invoices

Invoices are generated on the Spring Boot backend on order confirmation, not on-device — ensuring tamper-proof records pushed directly to device Downloads and accessible from order history.

Development Phases

01

Requirements

Kick-off & scope

02

UI / UX Design

Wireframes & approval

03

Core Dev

Auth & payments

04

Data Layer

SQLite + Firebase

05

Advanced

Maps, FCM, Biometrics

06

QA

Unit & security tests

07

Deployment

Hosting & review

08

Delivery

Docs & viva

Future Enhancements

🤖

AI Virtual Fit-On

ML avatar from body measurements for realistic try-on before purchase.

📷

AR Try-On

Real-time augmented reality clothing overlay using the device camera.

₿

Crypto Payments

Bitcoin and digital assets alongside emerging mobile wallet integrations.

✨

AI Style Assistant

Personalised fashion recommendations driven by purchase history.

🏆

Loyalty Program

Digital reward points and membership tiers for customer retention.

📊

Analytics Suite

BI dashboard for sales trend tracking and customer behaviour analysis.

DeesFashion