Assignments > Tutorial 6: Event Handlers

Due on Wed, 11/03 @ 11:59PM. 3 Points.

Tutorial Starter Files

The goal of this tutorial is to get you more comfortable with event handlers, and in particular the click, drag, and keyboard event handlers. Please complete the following exercises:

1. Add a creature when you click on the canvas

Open 01_click_to_add_creature.py and complete the following tasks:

1. modify the add_new_creature function so that it adds a new creature wherever the user clicks. Make the size and color of the creature random.
2. When you’re done, add the following line to your program right below your MOUSE_CLICK event handler:
   
   canvas.bind(MOUSE_DRAG, add_new_creature)
   
   Now run your program again, and notice that your add_new_creature function is invoked when you either click or drag.
3. Finally, replace the smiley face make_creature function with *your creature. To do this, copy your creature function (and any relevant helper functions) into creature.py and then make any necessary modifications to the add_new_creature function.

2. Move your creature when you press the i, j, k, and m keys

Open 02_move_creature_with_keyboard.py and complete the following tasks:

1. When the user presses the i-key, move the creature up 10 pixels.
2. When the user presses the j-key, move the creature to the left 10 pixels.
3. When the user presses the k-key, move the creature to the right 10 pixels.
4. When the user presses the m-key, move the creature down 10 pixels.

NOTES:

1. In order for your Canvas to listen for keyboard events, you must invoke the canvas.focus_set() method after you invoke canvas.pack() (at the top of your program). Without canvas.focus_set(), your keyboard events will not fire.
2. Also, the keyboard bindings for a Mac and a Windows are different. So in order for your program to work, you’ll need to make sure that you learn what the correct keyboard codes are for your operating system. Do do this, simply run your program, press a key, and see which code prints to the screen.

3. Select which creature to move with the keyboard

In the third exercise, you are going to use a global variable to track which creature your keyboard will control. To do this, you will combine the use of the click event handler and the keyboard event handlers.

Open 03_select_which_creature_to_move_with_keyboard.py and do the following:

1. Replace your move_creature function with the solution you came up with in exercise #2.
2. Create a global variable called active_tag and initialize it to ‘creature_1’.
3. Update your move_creature functionality so that instead of always moving ‘creature_1’, you reference the active_tag variable instead.
4. Modify the select_creature function so that it sets the active_tag variable based on creature on which the user clicks. Hint: use the global keyword.
5. Test your code by making sure that when you click on a different creature, the keyboard moves the correct one.

What to turn in (same deal as always)

Please turn in your completed tutorial exercise(s) ON CANVAS by Wednesday night at midnight. To do this, first zip your entire tutorial06 folder (with your edited files inside), and then upload your zip file to Canvas. Please ensure that your zip file includes YOUR CODE.