Task Tracker Project - Part 3

Let's think this through for a second

In this final stage, we'll fix the problem where the app from Part 2 loses its data every time it runs by using File I/O to save and load the task list from disk. To keep the display format consistent, we'll pull it out into a Formatter module and write it as a module method (self.line) — a practical use of the modules concept. When the app starts, we'll also show a welcome message and command list to make the user experience nicer. By the end of this stage, you'll own a small command-line project that pulls together Ruby's class, module, file handling, block, and iterator concepts.

Let's build it for real

Write the Formatter module with a def self.line(task, index) method that returns a string combining a status icon (✔ or a space), the index, and the title — update list_tasks to call this module method. Add a save(filename) method to the TaskTracker class that uses File.open(filename, "w") do |f| to write each task to the file in "title|done" format. The load(filename) method should check whether the file exists with File.exist?, and if it does, use File.readlines to split each line with split("|") and rebuild new Task objects. When the app starts, call tracker.load first, and when the exit command comes in, call tracker.save to persist the data. Finally, show a help message listing the available commands when the app starts up.

• Created the Formatter module and used it in the list_tasks display logic
• Can persist task data to a file with both the save and load methods
• Wired things up so the app loads on startup and saves automatically on exit

Code Example

module Formatter
  def self.line(task, index)
    status = task.done ? "✔" : " "
    "#{index}. [#{status}] #{task.title}"
  end
end

class TaskTracker
  def save(filename = "tasks.txt")
    File.open(filename, "w") do |f|
      @tasks.each { |t| f.puts "#{t.title}|#{t.done}" }
    end
  end

  def load(filename = "tasks.txt")
    return unless File.exist?(filename)
    @tasks = File.readlines(filename).map do |line|
      title, done = line.strip.split("|")
      task = Task.new(title)
      task.done = (done == "true")
      task
    end
  end

  def list_tasks
    @tasks.each_with_index { |task, i| puts Formatter.line(task, i + 1) }
  end
end

tracker = TaskTracker.new
tracker.load
puts "Task Tracker - commands: list / add <title> / done <no> / exit"

loop do
  print "> "
  input = gets.chomp
  break if input == "exit"
  # Part 2 ရဲ့ case/when logic ကို ဒီနေရာမှာ ဆက်သုံးပါ
end
tracker.save

After closing and reopening the app, it should load the data from tasks.txt and show your previous task list exactly as it was.