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CASE FILE #006STATUS: COMPLETED
Source Code

CashFlowku (Java Edition)

Role: Native Android Developer • Year: 2026

I built CashFlowku to help MSME (UMKM) owners manage sales transactions, inventory, and net profit offline without cloud dependency. Built with Java and native SQLite on Android, it features a Bento Grid financial dashboard (Net Profit, COGS, Gross Profit, Expenses), automated stock deductions, PDF summary generation, interactive CSV exports with live Excel formulas, and SQLite WAL backup verification.

JavaAndroid SDKSQLiteMaterial DesignAndroidX

Application Screenshots & Gallery

6 Images
CashFlowku (Java Edition) - Screenshot 1
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CashFlowku (Java Edition) - Screenshot 2
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CashFlowku (Java Edition) - Screenshot 3
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The Problem Context

Small business owners often struggle with cloud POS apps that require stable internet, lack net profit margin calculations (COGS/HPP), and risk data corruption during backups.

The Engineering Solution

I developed an offline-first native Android POS & bookkeeping app with real-time net profit calculations, inventory stock tracking, interactive CSV export with live Excel math formulas (=SUM, =Qty*Price), and SQLite WAL backup verification.

SYSTEM ARCHITECTURE TOPOLOGYInteractive Topology
STEP 01
Bento Grid Material UI
ConstraintLayout, RecyclerView & Dark Mode
FRONTEND LAYER
STEP 02
POS & Financial Logic
Java Native Controllers (JDK 17, Target SDK 34)
LOGIC LAYER
STEP 03
SQLite Local Persistence
SQLiteOpenHelper & WAL Checkpoint Engine
DATABASE LAYER
STEP 04
Export & Backup Engine
PDF Bento Cards & Formula CSV Generator
EXPORT LAYER
SELECTED NODE:Bento Grid Material UI
Click any node to inspect

Implementation Highlights

01.

Engineered Bento Grid real-time financial dashboard calculating Net Profit (Omset - HPP - Expenses), Gross Profit, and HPP.

02.

Built POS inventory management with automated stock deduction, COGS input, and photo attachments.

03.

Developed ExportUtil generating PDF summary cards and interactive CSV files embedded with dynamic Excel formulas.

04.

Implemented SQLite Write-Ahead Logging (WAL) checkpointing and SQLite header verification for safe backups.

05.

Integrated bi-directional settings synchronization between SQL key-value tables and SharedPreferences with Dark Mode.

Measurable Results

  • 100% offline data privacy with zero cloud dependencies.
  • Instant sub-50ms SQLite database query response and smooth theme switching.
  • Automated financial report generation with auto-recalculating spreadsheet exports.

Key Lessons Learned

  • SQLite WAL checkpointing is vital for offline mobile apps to prevent backup state desynchronization.
  • Generating CSV files with native spreadsheet formulas provides great value for business accounting workflows.