Calculator with History

A Flutter calculator application developed as part of my mobile development learning journey. While building on the foundation of a traditional calculator app, I enhanced it with persistent calculation history and interactive features to create a more practical tool.

Overview

This project implements a standard arithmetic calculator with additional functionality for storing and reusing calculation history. The application demonstrates fundamental Flutter concepts while incorporating useful features that extend beyond typical beginner calculator projects.

Key Features

Persistent Calculation History: All calculations are stored locally using the Hive package, ensuring data persists between app sessions. This provides users with a complete record of their computational work.

Interactive History: Previous calculation results can be selected and integrated into new calculations, enabling multi-step problem solving and result verification.

Gesture-Based Management: Implemented swipe-to-delete functionality instead of a backspace button.

Theme Customization: Light and Dark theme options.

Technical Implementation

Framework: Built with Flutter and Dart, utilizing the framework's widget-based architecture for component organization and state management.

Data Storage: Integrated Hive for local data persistence, chosen for its simplicity and performance characteristics suitable for mobile applications.

Mathematical Processing: Utilized the math_expressions package for reliable parsing and evaluation of arithmetic expressions.

State Management: Implemented Provider pattern for managing application state and data flow between components.

UI Design: Followed Material Design principles with layout inspiration from Lucia Scott's Dribbble design.

Development Approach

I approached this project as an opportunity to explore Flutter development beyond basic tutorials. While the core calculator functionality follows conventional patterns, I focused on adding practical features that would make the application genuinely useful.

The history functionality emerged from personal experience with mobile calculators and the frequent need to reference or build upon previous calculations. Rather than treating each calculation in isolation, I designed the app to support workflow continuity.

The technical choices reflected a balance between learning objectives and practical implementation. Hive provided an accessible introduction to local data storage without the complexity of full database management, while the math_expressions package allowed focus on app architecture rather than mathematical parsing logic.

Learning Outcomes

This project served as practical experience with several Flutter development concepts:

• Widget composition and state management patterns
• Local data persistence and storage strategies
• Mobile UI/UX considerations and gesture handling
• Component architecture and code organization
• Material Design implementation and theming systems

The development process reinforced the importance of considering user workflow when designing features, as the history reuse functionality proved more valuable in practice than initially anticipated.

Demo Video