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Session 7: Milestone project work day 1

Phase 5 — customtkinter · Session 7 of 8

What we’re learning today

Today is your day. You’ll plan a desktop app of your own design — your idea, your widgets, your behavior — and start building it. Next week you’ll finish it and demo it to the class.

You’ll need to remember from last time

  • The widget toolbox — labels, buttons, entries, checkboxes, radios, dropdowns, frames.
  • pack and grid for layout.
  • Callbacks with command=.
  • The redraw pattern — state + a refresh function.
  • Persistence with JSON (Session 6 stretch).
  • Git (Phase 4 Sessions 5-6) — commit as you go.

Part A: Plan your app

Same shape as previous milestones, with new requirements specific to Phase 5.

The plan

Take a piece of paper or open a blank text file. Answer these six questions:

  1. What’s the app? (One sentence. “A flashcard quiz.” “A budget tracker.” “A drawing pad.”)

  2. What does the user do with it? (How do they interact? What do they click? What do they type?)

  3. What widgets will it have? (Labels, entries, buttons, lists, checkboxes? Sketch the window on paper if it helps.)

  4. What state does it track? (A list of items? A single value? A dictionary?)

  5. What’s the simplest version? (Build this FIRST. No persistence, no fancy features — just the core.)

  6. Will it save data to a file? (Optional but recommended. JSON for lists/dicts, plain text for single values.)

If you don’t have an idea

Pick one and modify:

  • A flashcard app — load questions from a file, show one at a time, click to reveal the answer, next button.
  • A budget tracker — add expenses with category and amount, show running totals, save to JSON.
  • A drawing pad — CTkCanvas (similar to Phase 2 turtle world), click and drag to draw lines.
  • A timer / pomodoro app — set a duration, click start, watch the countdown.
  • A dice roller for tabletop games — pick number of dice, click roll, show results.
  • A unit converter — pick from/to units, type a value, see the result.
  • A simple text editor — CTkTextbox, save/load buttons, file path entry.
  • A character sheet for a game — name, stats, items (extension of Session 4’s character builder, with save).
  • A quiz game — multiple choice questions, score tracking, end screen.
  • A music player UI — list of songs, play/pause/skip buttons. (The buttons can fake it — print to console instead of actually playing audio.)
  • A memory match game — grid of buttons that flip to reveal images or letters; match pairs.

Pick one. Spend two minutes. Don’t overthink.

Show Mr. Eric

When your plan is ready, show it to Mr. Eric. He’ll either say “go build it” or ask one question.

Set up the project

Create a folder for your project. Open a terminal:

$ cd ~                          # or wherever you keep projects
$ mkdir my_app                  # use your project's name
$ cd my_app
$ git init

Create your main file (probably main.py or app.py) and commit it before writing much:

$ git add main.py
$ git commit -m "Initial project setup"

Commit early, commit often. Each meaningful change gets its own commit.

Build the simplest version first

Look at your answer to question 5. Build that first. Get a window on screen. Get the most important widget working. Wire up one callback. Then iterate.

For each significant change:

  1. Make the change.
  2. Run it. Make sure it works.
  3. Commit (git add ...; git commit -m "...").
  4. Move to the next thing.

If your widgets are getting unwieldy and there are lots of top-level globals, wrap your code in a class (like Session 6’s class refactor). Real apps tend to grow into classes.

If something feels risky (a big change you might want to undo), make a branch:

$ git checkout -b try-new-thing
# ... experiment ...
$ git checkout main
$ git merge try-new-thing       # if it worked
# OR
$ git branch -D try-new-thing   # if it didn't

Wrap-up

Last 5 minutes: each of you, in one sentence, tell the room one thing you got working today. Bonus points for showing a screenshot.

Bring your project (the folder — Git carries the history) next week. We’ll finish, then demo.

If you missed this session

Open Thonny and a terminal. Then:

  1. Spend 10-15 minutes answering the six planning questions.

  2. Create a folder for your project. git init in it. Create your first file. Commit.

  3. Build the simplest version. Commit as you go (every few meaningful changes).

About 60-75 minutes total — planning + a substantial first build. If you can show your buddy a window with at least one working button next week, you’re ready for Day 2.

If you don’t have an idea, the seed list above is a starting point. Pick one and modify.

Stretch and extension ideas

If your base project is working and you want to add more:

  • Add JSON persistence so state survives between runs (Session 6 pattern).
  • Refactor to a class if you started with globals (Session 6 stretch).
  • Add a Settings dialog with CTkToplevel — a separate window for app preferences.
  • Style it — try ctk.set_appearance_mode("dark") and ctk.set_default_color_theme("green") near the top.
  • Use a branch to try a feature without breaking main. Merge if it works.
  • Add a menu bar with File / Edit / View options (advanced — tkinter.Menu).
  • Make it resizable nicely — use grid weights so things scale with the window.
  • Add icons — buttons can have images via image=.

Whatever you add, commit each change. Future you wants to see the journey.

What’s next

Next week is the last session of Phase 5. You’ll have time to finish, polish, and demo your app to the class. Each person gets 3-5 minutes. Bring a working app, your enthusiasm, and your Git log — part of the demo will be showing the journey of how your app came together.