WK4: Hands-on Event-Driven Programming with Tkinter

• Programming
• Higher Education (degree)

Welcome to Session 2

Hands-on Event-Driven Programming with Tkinter

Module Lecturer: Dr Raghav Kovvuri

Email: [e-mail]

Introduction to Tkinter

• Tkinter: Python's standard GUI (Graphical User Interface) package
• Event-Driven Programming recap

• Programs respond to events (e.g., button clicks, key presses)
• Main event loop listens for and handles events

Basic Tkinter Widgets

Common widgets:

1. Button
2. Label
3. Entry (text input)
4. Checkbutton
5. Radiobutton

Example:

Exercise: Create a window with a label and a button

Handling Events in Tkinter

Event binding:

• Connect a function to a widget event

Exercise: Modify the button to change the label text when clicked

Layout Management

Tkinter geometry managers:

1. pack() - simple
2. grid() - table-like
3. place() - precise positioning

Grid example:

Exercise: Create a login form with username and password fields

 Discussion - Event Types

Common Tkinter events:

• <Button-1>: Left mouse click
• <Key>: Any key press
• <Return>: Enter key press
• <FocusIn>: Widget gains focus
• <MouseWheel>: Mouse scroll

Question: Can you think of other useful events for our calculator?

Advanced Event Handling

Multiple event bindings:

Exercise: Add keyboard support to your calculator (number keys and operators)

Error Handling in GUI Applications

Importance of error handling in GUIs:

• Prevent crashes
• Provide user feedback

Example:  Implement error handling in your calculator

Task: Extending the Calculator

Implement two ideas:

1. Implement memory functions (M+, M-, MR, MC)
2. Add square root and power functions
3. Create a scientific calculator mode

Hands on Exercise

Recap

Key points:

• Event-driven programming responds to user actions
• Tkinter provides a simple way to create GUIs in Python
• Proper event handling and error management are crucial