Flutter Calculator

A modern, feature-rich calculator app built with Flutter that provides basic arithmetic operations with a clean and intuitive user interface.

Features

• Basic Arithmetic Operations: Addition (+), Subtraction (-), Multiplication (×), Division (÷)
• Advanced Functions:
  • Percentage calculations (%)
  • Decimal point support
  • Double zero (00) input for faster entry
• User Interface:
  • Clean, modern design with rounded buttons
  • Real-time equation display
  • Large, easy-to-read result display
  • Responsive button layout
• Functionality:
  • Clear all (AC) function
  • Backspace (⌫) for correcting input
  • Error handling for invalid expressions
  • Fullscreen toggle mode
  • History menu for viewing past calculations

Screenshots

The calculator features a clean interface with:

• Display area showing both the current equation and result
• Number pad with digits 0-9
• Operation buttons with distinctive orange styling
• Function buttons for clear, backspace, and percentage
• History feature to view past calculations

Getting Started

Prerequisites

• Flutter SDK (3.7.2 or higher)
• Dart SDK
• Android Studio / VS Code with Flutter extensions
• An Android/iOS device or emulator

Installation

1. Clone the repository:

git clone <repository-url>
cd calculator

2. Install dependencies:

flutter pub get

3. Run the app:

flutter run

Dependencies

Runtime Dependencies

• flutter: The Flutter SDK
• math_expressions: ^2.4.0 - For parsing and evaluating mathematical expressions
• cupertino_icons: ^1.0.8 - iOS-style icons

Development Dependencies

• flutter_test: Flutter testing framework
• flutter_lints: ^5.0.0 - Recommended lints for Flutter projects

Environment

• Dart SDK: ^3.7.2
• Flutter: Compatible with Flutter 3.7.2+

Project Structure

calculator/
├── android/               # Android-specific files
├── ios/                   # iOS-specific files  
├── linux/                 # Linux-specific files
├── windows/               # Windows-specific files
├── lib/                   # Main Dart source code
│   ├── main.dart          # Main application entry point
│   ├── buttons/
│   │   └── button.dart    # Custom button widgets
│   └── history.dart       # History page for viewing past calculations
├── test/                  # Unit and widget tests
├── pubspec.yaml           # Project dependencies and metadata
├── pubspec.lock           # Locked dependency versions
├── analysis_options.yaml # Dart analysis configuration
├── .gitignore            # Git ignore rules
└── README.md             # Project documentation

Ignored Files and Directories

This project uses a comprehensive .gitignore file to exclude:

Build and Generated Files

• build/ - Flutter build outputs
• .dart_tool/ - Dart tooling cache
• *.iml - IntelliJ module files
• Generated plugin registrant files

IDE and Editor Files

• .idea/ - IntelliJ IDEA configuration
• .vscode/ (optional) - VS Code configuration
• .DS_Store - macOS system files

Platform-Specific Build Artifacts

• Android: /android/app/debug, /android/app/profile, /android/app/release
• iOS: DerivedData, Pods, xcuserdata, and other Xcode artifacts
• Windows/Linux: Generated plugin files

Dependencies and Cache

• .packages - Package resolution cache
• .pub-cache/ - Pub package cache
• pubspec.lock is tracked but build artifacts are ignored

Custom Additions

• .qodo/ - Qodo AI assistant files
• .env* - Environment configuration files
• *.tmp, *.temp - Temporary files

Key Components

Main Calculator (main.dart)

• Contains the main calculator logic and UI
• Handles button press events and calculations
• Manages state for equation display and results
• Implements error handling for invalid expressions

Custom Buttons (buttons/button.dart)

• CustomRawMaterialButton: Standard number buttons
• CustomRawMaterialButton2: Operation buttons with orange styling
• CustomRawMaterialButton3: Equals button with filled orange background

History Page (history.dart)

• Displays past calculations and allows users to recalculate previous entries

How It Works

1. Input Handling: Users tap buttons to input numbers and operations
2. Expression Building: The app builds a mathematical expression string
3. Real-time Display: Shows both the current equation and result
4. Calculation: Uses the math_expressions package to parse and evaluate expressions
5. Result Display: Shows the calculated result with proper decimal handling
6. History Feature: Users can view and recalculate previous entries

Features in Detail

Percentage Calculation

• Converts the last entered number to its percentage equivalent
• Works with both standalone numbers and numbers in expressions

Smart Input Handling

• Prevents multiple consecutive operators
• Handles decimal point input validation
• Supports continuing calculations with previous results

Error Handling

• Displays "Error" for invalid mathematical expressions
• Gracefully handles division by zero and other edge cases

Building for Production

Android

flutter build apk --release

iOS

flutter build ios --release

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/new-feature)
3. Commit your changes (git commit -am 'Add new feature')
4. Push to the branch (git push origin feature/new-feature)
5. Create a Pull Request

Future Enhancements

• Implement calculation history storage and display
• Add scientific calculator functions
• Theme customization options
• Memory functions (M+, M-, MR, MC)
• Keyboard input support
• Landscape mode optimization

License

This project is open source and available under the MIT License.

Support

If you encounter any issues or have suggestions for improvements, please create an issue in the repository.

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Built with ❤️ using Flutter By Ardawan M Amin