ExpenseTracker

💸 ExpenseTracker

A fully-featured personal expense tracking app built as a native Android application using a WebView-based architecture. No sign-in required. All data stored locally on your device.

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📱 Screenshots

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✨ Features

💰 Transactions

• Add income and expense transactions
• Set description, notes, category, date and time
• Attach receipt photos from gallery
• Mark transactions as recurring monthly — auto-added every month
• Edit or delete any transaction
• Search transactions by description or notes
• Filter by category chips

📊 Analytics

• Monthly income, expenses, net balance and average expense
• Navigate between months
• Spending breakdown by category (tap to see all transactions in that category)
• 6-month comparison bar chart
• 14-day daily spending chart

💡 Budgeting

• Set an overall monthly budget with a live progress bar on the home screen
• Set per-category budgets with progress bars and alerts
• Budget rollover — carry unspent budget from last month to this month
• View, edit and delete all budgets in one screen
• Warnings when approaching or exceeding any budget

🏷️ Categories

• 16 built-in categories (Food, Transport, Shopping, Bills, Health, Fun, Home, Education, Travel, Fitness, Savings, Salary, Freelance, Gift, Other, Coffee)
• Edit any default category — change name and emoji
• Hide categories you don’t use
• Create custom categories with any emoji from your keyboard
• Delete custom categories

📤 Data Transfer

• Export full backup (JSON) — includes all transactions, settings, budgets, categories and receipt photos
• Export as Excel — choose date range (this month / 3 months / 6 months / all time / custom), generates 3 sheets: Transactions, By Category, Monthly Summary
• Import from JSON backup — merges with existing data, restores photos
• Designed for switching phones without losing any data

🎨 Quality of Life

• Dark / Light theme toggle
• PIN lock — set a 4-digit PIN to protect the app
• Currency selector — supports any symbol ($ € £ ₹ ¥ etc.)
• Biggest expense of the month highlighted on home screen
• Pull-to-refresh prevention (no accidental reloads)
• Keyboard-aware popups (forms slide above keyboard)

🏠 Home Screen Widgets

• Add Expense widget — tap to instantly open the add transaction screen
• Recent Expenses widget — shows your 5 most recent expenses with emoji, description, amount and time, updates automatically

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🛠️ Tech Stack

Layer	Technology
Android wrapper	Kotlin + WebView
UI	HTML, CSS, JavaScript (single file)
Storage	localStorage (WebView) + SharedPreferences (widget)
Excel export	SheetJS (xlsx.js)
Fonts	Google Fonts (Syne + DM Mono)
Build	Android Studio, Gradle 8.2
Min SDK	Android 7.0 (API 24)
Target SDK	Android 14 (API 34)

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🚀 Getting Started

Prerequisites

• Android Studio (latest stable)
• JDK 17 or 19 (not 21 — incompatible with Gradle 8.2)
• An Android phone running Android 7.0+

Build & Run

1. Clone the repository:

   git clone https://github.com/YOUR_USERNAME/ExpenseTracker.git
   

2. Open the project in Android Studio:
   • File → Open → select the ExpenseTracker folder

3. Wait for Gradle to sync (first time may take a few minutes)

4. Build the APK:
   • Build → Build Bundle(s) / APK(s) → Build APK(s)
   • APK will be at app/build/outputs/apk/debug/app-debug.apk
5. Install on your phone:
   • Transfer the APK to your phone
   • Enable Install unknown apps in your phone settings
   • Tap the APK to install

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📂 Project Structure

ExpenseTracker/
├── app/src/main/
│   ├── assets/
│   │   └── index.html          # Entire app UI (HTML/CSS/JS)
│   ├── java/com/expensetracker/
│   │   ├── MainActivity.kt     # WebView host + JS bridge
│   │   ├── ExpenseWidget.kt    # Add Expense home screen widget
│   │   └── RecentExpensesWidget.kt  # Recent Expenses widget
│   ├── res/
│   │   ├── layout/
│   │   │   ├── activity_main.xml
│   │   │   ├── widget_add_layout.xml
│   │   │   └── widget_recent_layout.xml
│   │   ├── xml/
│   │   │   ├── widget_add_info.xml
│   │   │   ├── widget_recent_info.xml
│   │   │   └── file_paths.xml
│   │   └── drawable/
│   │       └── widget_background.xml
│   └── AndroidManifest.xml

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🔄 Switching Phones

All your data (transactions, photos, budgets, settings) can be transferred between phones:

1. On your old phone: Settings → Export Backup (JSON)
2. Copy the .json file to your new phone (WhatsApp, Google Drive, USB, etc.)
3. On your new phone: Settings → Import Data → select the file
4. Everything is restored including receipt photos

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🔐 Privacy

• No internet connection required after first load (fonts are cached)
• No account or sign-in of any kind
• No data leaves your device — everything is stored in local storage
• No ads, no tracking, no analytics

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📋 Permissions

Permission	Reason
INTERNET	Load Google Fonts on first launch
READ_EXTERNAL_STORAGE	Import backup files
WRITE_EXTERNAL_STORAGE	Save exported files to Downloads (Android ≤ 9)
READ_MEDIA_IMAGES	Pick receipt photos from gallery (Android 13+)

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🧑‍💻 Development Notes

JS ↔ Android Bridge

The app communicates between JavaScript and Kotlin via @JavascriptInterface:

// Called from JS to save a file
fun exportData(data: String, filename: String, encoding: String)

// Called from JS to refresh the Recent Expenses widget
fun updateWidget(recentJson: String)

// Called from JS to trigger the file picker
fun triggerImport()

Adding the Widgets

After installing the app:

1. Long press your home screen
2. Tap Widgets
3. Find ExpenseTracker
4. You’ll see two widgets — drag either one to your home screen

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📄 License

This project is for personal use.

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👤 Author

Created by ∅M