Task Manager App (Protocol-Oriented Programming in Swift)

Overview

This is a sample Task Manager app built with UIKit to demonstrate Protocol-Oriented Programming (POP) in Swift. The app allows users to:

• Add tasks with a title and optional description.
• Mark tasks as completed.
• Delete tasks by swiping.
• View task details.
• Persist tasks using UserDefaults.

Key Concepts

This project follows Protocol-Oriented Programming (POP) principles by using:

1. TaskRepresentable (Defines Task Structure)

protocol TaskRepresentable {
    var title: String { get }
    var description: String? { get }
    var isCompleted: Bool { get set }
}

2. TaskPersistable (Handles Data Persistence)

protocol TaskPersistable {
    func saveTasks(_ tasks: [Task])
    func loadTasks() -> [Task]
}

3. TaskManagerProtocol (Manages Task Operations)

protocol TaskManagerProtocol {
    var tasks: [Task] { get set }
    func addTask(_ task: Task)
    func updateTask(_ task: Task)
    func filterTasks(by completionStatus: Bool) -> [Task]
}

Implementation

Task Model

struct Task: TaskRepresentable, Codable {
    var title: String
    var description: String?
    var isCompleted: Bool
}

Task Manager

Handles task storage and retrieval using UserDefaults.

class TaskManager: TaskManagerProtocol, TaskPersistable {
    var tasks: [Task] = []

    func addTask(_ task: Task) {
        tasks.append(task)
        saveTasks(tasks)
    }

    func updateTask(_ task: Task) {
        if let index = tasks.firstIndex(where: { $0.title == task.title }) {
            tasks[index] = task
            saveTasks(tasks)
        }
    }

    func filterTasks(by completionStatus: Bool) -> [Task] {
        return tasks.filter { $0.isCompleted == completionStatus }
    }

    func saveTasks(_ tasks: [Task]) {
        let encoder = JSONEncoder()
        if let encoded = try? encoder.encode(tasks) {
            UserDefaults.standard.set(encoded, forKey: "tasks")
        }
    }

    func loadTasks() -> [Task] {
        if let savedTasks = UserDefaults.standard.data(forKey: "tasks") {
            let decoder = JSONDecoder()
            if let loadedTasks = try? decoder.decode([Task].self, from: savedTasks) {
                tasks = loadedTasks
                return loadedTasks
            }
        }
        return []
    }
}

UI Implementation

Task List Screen (TaskListViewController)

• Displays tasks in a table view.
• Allows users to mark tasks as completed.
• Supports swipe-to-delete.

Add Task Screen (AddTaskViewController)

• Users enter a title and description.
• Task is added and saved.

Task Detail Screen (TaskDetailViewController)

• Shows task details when a task is tapped.

Running the Project

1. Clone the repository.
2. Open TaskManager.xcodeproj in Xcode.
3. Run the app on a simulator or device.

Future Improvements

• Implement filtering (e.g., show only completed tasks).
• Use CoreData instead of UserDefaults for persistence.
• Add unit tests for TaskManager.

Conclusion

This project showcases how Protocol-Oriented Programming (POP) helps in creating modular, reusable, and scalable code. The use of protocols promotes composition over inheritance, making the codebase cleaner and more maintainable.