BMI Calculator Android App - Health Tracker

BMI Calculator is a complete and professional Android application developed using Java and XML. The app is designed to help users easily calculate their Body Mass Index (BMI) and understand their overall health condition through clear and accurate results.

In addition to standard BMI calculation, the app provides advanced health metrics including Basal Metabolic Rate (BMR), Body Fat Percentage, and Ideal Weight. These calculations are based on user input such as age, gender, height, weight, and activity level, allowing more accurate and meaningful results.

The application supports both Metric and Imperial unit systems, making it suitable for users worldwide. A simple unit toggle allows users to switch units instantly without confusion.

The app also includes a weight history feature where users can track their weight over time. All stored weight entries are displayed using a clean and modern line chart, helping users visualize progress clearly and effectively.

Users can export their health results as a PDF report, which can be easily shared or saved for future reference. All calculations and data processing are performed locally on the device to ensure user privacy.

The project is built with a clean and well-organized code structure, following best practices for Android development. The UI is based on Material Design components and is fully reskinnable, allowing quick customization of colors, icons, text, and layouts.

Monetization is supported through AdMob Banner and Interstitial Ads, which are already integrated and easy to configure by replacing the test ad unit IDs with your own.

This source code is ideal for developers who want to publish a health or fitness-related app quickly, or for learning purposes to understand real-world Android app architecture using Java and XML.

Note: This application is intended for informational purposes only. Health calculations are estimations and should not be considered medical advice.

Features

• 📊 BMI Calculation – Instantly calculate Body Mass Index with clear health categories
• 🔥 BMR Calculation – Calculate Basal Metabolic Rate based on age, gender, and activity level
• 💧 Body Fat Percentage – Estimate body fat for better health understanding
• ⚖️ Ideal Weight – Get recommended ideal body weight range
• 🌍 Metric & Imperial Units – Support for kg/cm and lbs/ft/in units
• 🚻 Gender Selection – Male & Female support for accurate calculations
• 🏃 Activity Level Selection – Sedentary to Very Active options
• 📈 Weight History Tracking – Save and track weight progress over time
• 📉 Line Chart Visualization – Visual weight progress with interactive charts
• 📄 PDF Report Export – Export and share detailed health reports
• 🎨 Material Design UI – Clean, modern, and user-friendly interface
• 🧩 Easy Reskin – Quickly customize app name, colors, icons, and layouts
• 💰 AdMob Integration – Banner & Interstitial Ads included for monetization
• 🔒 Offline & Privacy Friendly – All calculations done locally on device

Requirements

• Android Studio (latest version recommended)
• Minimum Android Version: Android 7.0 (API 24)
• Target SDK: 36+
• Java Development Kit (JDK 8 or higher)
• Basic knowledge of Java and XML
• Google AdMob account (for ad monetization)
• Physical Android device or emulator for testing

Instructions

1. Download and extract the source code ZIP file.
2. Open Android Studio.
3. Select Open an Existing Project.
4. Choose the project root folder and wait for Gradle sync to complete.
5. Open the documentation/index.html file for detailed project overview and setup instructions.
6. Read the README.md file for reskin steps, build instructions, and AdMob configuration.
7. Change app name from res/values/strings.xml.
8. Change package name using Refactor → Rename → Rename Package in Android Studio.
9. Replace app icons inside all mipmap folders with your own icons.
10. Update app colors from res/values/colors.xml.
11. Replace test AdMob IDs with your own Banner and Interstitial Ad Unit IDs.
12. Run the app on a real device or emulator to test.
13. Generate a signed APK or AAB from Build → Generate Signed Bundle / APK for release.