Introduction to GUI Programming with Tkinter
Python provides a powerful toolkit for building graphical user interfaces (GUIs), Tkinter. It is part of the standard Python library and provides a simple and intuitive way to create graphical applications. Tkinter is built on top of the Tcl/Tk GUI framework, and is available on most platforms, including Windows, Linux and macOS.
Getting Started with Tkinter
To get started with Tkinter, you need to import the module:
import tkinter as tk
This will create a Tkinter instance, to which you can add widgets and other elements. To create a window, you can use the
tk.Tk() method. This will create a top-level window, which will be the parent of all other widgets.
Creating Widgets with Tkinter
Once you have a window, you can start adding elements to it. Tkinter provides a variety of widgets, such as buttons, labels, frames, and scrollbars. To add a widget to a window, you can use the
window.add() method. For example, to add a label to a window, you can use the following code:
label = tk.Label(window, text="Hello, World!")
label.pack()
This will create a label with the text "Hello, World!" and add it to the window.
Event Handlers with Tkinter
To make your GUI interactive, you need to add event handlers. Tkinter provides a variety of event handlers, such as
on_click,
on_key, and
on_mouse. For example, to add an event handler to a button, you can use the following code:
def on_click(event):
print("Button was clicked!")
button = tk.Button(window, text="Click me!")
button.bind("", on_click)
button.pack()
This will create a button with the text "Click me!" and add an event handler that will print "Button was clicked!" when the button is clicked.
Example: Building a Simple Calculator
To show how to use Tkinter, let's build a simple calculator. First, we need to create a window and add the following elements to it:
- A label for displaying the result
- Four buttons for the numbers 0-3
- Two buttons for the operations + and -
- A button for computing the result
The following code will create the window and add the elements:
# Create window
window = tk.Tk()
window.title("Calculator")
# Create result label
result = tk.Label(window, text="0")
result.pack()
# Create number buttons
for i in range(0, 4):
b = tk.Button(window, text=str(i))
b.pack(side="left")
# Create operation buttons
plus = tk.Button(window, text="+")
plus.pack(side="left")
minus = tk.Button(window, text="-")
minus.pack(side="left")
# Create compute button
compute = tk.Button(window, text="=")
compute.pack(side="left")
Now, we need to add event handlers to the buttons. We will add one handler for the number buttons, and one for the operation buttons.
# Number button handler
def on_number(event):
result["text"] = event.widget["text"]
# Add handler to number buttons
for i in range(0, 4):
b = window.children['!button' + str(i)]
b.bind("", on_number)
# Operation button handler
def on_operation(event):
operation = event.widget["text"]
if operation == "+":
result["text"] = str(int(result["text"]) + 1)
elif operation == "-":
result["text"] = str(int(result["text"]) - 1)
# Add handler to operation buttons
plus.bind("", on_operation)
minus.bind("", on_operation)
# Compute button handler
def on_compute(event):
result["text"] = str(eval(result["text"]))
# Add handler to compute button
compute.bind("", on_compute)
Finally, we need to start the window's main loop:
window.mainloop()
Now, when you run the program, you should see a window with a calculator. You can enter numbers, add and subtract them, and compute the result.
Tips for GUI Programming with Tkinter
- Use the
window.add() method to add widgets to a window.
- Use the
window.children['!buttonX'] syntax to get a reference to a button.
- Use the
widget.bind() method to add event handlers to widgets.
- Use the
widget["text"] syntax to get or set the text of a widget.
- Use the
window.mainloop() method to start the window's main loop.
Conclusion
In this tutorial, we have covered the basics of GUI programming with Tkinter. We have seen how to create a window and add elements to it, how to add event handlers, and how to build a simple calculator. With the knowledge from this tutorial, you should be able to create basic GUI applications with Tkinter.