Kirana Store Credit Ledger Android App with Payment Reminders

Thousands of small kirana and general stores across India sell daily essentials on credit — "udhaar" — and track it in a paper notebook. That notebook gets lost, torn or disputed: the shopkeeper forgets who paid what, customers argue about the balance, and small dues quietly turn into defaults because nobody follows up systematically. The problem is not a lack of accounting software — it is that full accounting apps are too heavy for a small shopkeeper who needs exactly one thing: who owes how much, since when, and a nudge to collect. This project builds an Android app purpose-fit for that workflow: a per-customer credit ledger with item-level notes, running balances, an overdue aging list, and one-tap SMS reminder templates so the shopkeeper can follow up politely and consistently. It is offline-first — the app must work with no internet — using on-device storage, with scheduled local reminders and optional backup.

1. The shopkeeper adds a customer once (name, phone number) and starts recording credit sales with item notes and amounts.
2. Every entry updates the customer's running balance instantly — credits increase it, payments reduce it.
3. The overdue aging logic measures days since each account's last activity and ranks debtors oldest-first on the Reminders screen.
4. Each morning, a scheduled WorkManager task posts a local notification summarizing accounts needing follow-up.
5. The shopkeeper taps "Send SMS reminder" on an overdue account; the phone's SMS app opens with a polite pre-filled message, and the shopkeeper presses send.
6. Payments are recorded against the ledger in one step; the daily collection screen tallies today's cash and the 7-day average.
7. All records persist in the on-device Room database; an optional backup export can be enabled for safekeeping.

Tech stack:

• Android (Kotlin/Java)
• Room (SQLite) local database
• WorkManager (scheduled reminders)
• Material Design components
• Android SMS intent (pre-filled reminders)
• SharedPreferences (settings)
• Gradle build system

• [Per-customer credit ledger] Every customer gets a running ledger: each credit sale and payment is recorded with item notes (e.g. "Rice 5 kg, oil 2 L"), date, and an automatically updated running balance.
• [Overdue aging report] The app ages every outstanding balance from the last activity date and lists overdue accounts oldest-first, so the shopkeeper sees exactly who needs a nudge.
• [One-tap SMS reminder templates] Tapping "Send SMS reminder" opens the phone's SMS app with a pre-written polite reminder (name, amount, days pending) — the shopkeeper reviews and sends it.
• [Daily collection summary] Today's collected payments, today's count, and the 7-day average collection are shown on a dedicated screen for daily cash-flow visibility.
• [Scheduled local reminders] A WorkManager-based daily schedule surfaces the overdue list every morning as a local notification, working fully offline.
• [Offline-first local database] All data lives in an on-device Room/SQLite database — the shop keeps running with no internet; optional cloud backup can be added on request.
• [Customer search] Instant name search across the customer list for shops with hundreds of credit accounts.

• Complete Android app source code (Kotlin/Java) with build instructions
• Room database schema and data-access code
• Working demo build (APK) with realistic sample data
• Single-file interactive demo for presentation
• Project report PDF (background, architecture, methodology, results)
• PPT presentation for final review
• Viva Q&A preparation document (Android components, Room, WorkManager, offline-first design)