KotlinCalculatorApp is a simple calculator application I developed using Kotlin to keep my Android development skills sharp and up-to-date. It's a small side project I developed in my spare time, aiming to provide a clean and intuitive calculator experience on Android devices.
- Basic Arithmetic Operations: Perform addition, subtraction, multiplication, and division with ease.
- Percentage Calculation: Quickly calculate percentages for various purposes.
- Clear and Delete Functionality: Clear the input or delete the last character with the provided buttons.
- Error Handling: Proper error handling ensures smooth user experience even with complex expressions.
- Unit tests: Unit tests to ensure the correctness of calculation functions.
- UI/Integrated tests: Integrated tests to validate the user interface and integration of components.
The codebase of KotlinCalculatorApp is designed to be modular and maintainable. Here are some key design aspects:
- Compose UI: The user interface is built using Jetpack Compose, offering a modern and reactive approach to UI development on Android.
- Material 3 Design: The app follows Material 3 Design guidelines to ensure a visually pleasing and consistent user experience across different devices.
- mXparser Integration: The app utilizes the mXparser library for math expression parsing, avoiding reinventing the wheel and ensuring accurate calculation results.
The solveExpression function treats expressions ending with "%" as percentages, while others are interpreted as modulo operations. However, this can lead to unexpected behavior in certain cases.
Consider "20%÷2":
- "20%2" usually means taking 20% of 2, resulting in 0.40.
- Dividing 0.40 by 2 yields 0.20, not 0.10.
This discrepancy arises from the interpretation of "%" in combination with other operators, showcasing a potential inconsistency in calculator behavior. KotlinCalculatorApp consistently interprets "%" as a percentage regardless of context, ensuring predictable behavior.
It's worth noting that different calculators may interpret expressions differently. For example, if a different calculator yields 0.10 instead of 0.20 for the expression "20%÷2", it may be interpreting the expression in a manner different from the standard interpretation described above. Such variations highlight the importance of understanding the conventions of the specific calculator you are using.
Inputting expressions like "20%÷2" directly into KotlinCalculatorApp may cause a crash due to its strict interpretation. Future updates will address this issue. While this approach guarantees consistency, it's important to note differences from other calculator designs.
To run KotlinCalculatorApp locally, follow these steps:
- Clone this repository.
- Open the project in Android Studio or any compatible IDE.
- Build and run the project on an Android device or emulator.
Contributions to KotlinCalculatorApp are welcome! If you have any suggestions, enhancements, or bug fixes in mind, feel free to open an issue or submit a pull request.
Enjoy calculating with KotlinCalculatorApp! If you have any questions or feedback, don't hesitate to reach out.