Simple GUI-based calendar using the tkinter library and Python

Here’s a Python program that creates a simple GUI-based calendar using the tkinter library and Python’s built-in calendar module.

The program will display the calendar for a specified month and year.

Code

import tkinter as tk
import calendar

# Function to display the calendar for the given month and year
def show_calendar():
    try:
        # Get the year and month from the user inputs
        year = int(year_entry.get())
        month = int(month_entry.get())

        # Generate the calendar text
        cal_text = calendar.month(year, month)

        # Update the calendar display label with the generated calendar
        calendar_display.config(state="normal")
        calendar_display.delete("1.0", tk.END)  # Clear previous content
        calendar_display.insert(tk.END, cal_text)  # Insert the new calendar
        calendar_display.config(state="disabled")  # Make the text box read-only
    except ValueError:
        calendar_display.config(state="normal")
        calendar_display.delete("1.0", tk.END)
        calendar_display.insert(tk.END, "Please enter valid numbers for year and month.")
        calendar_display.config(state="disabled")

# Initialize the main window
root = tk.Tk()
root.title("Calendar Viewer")
root.geometry("300x300")

# Labels and entry fields for year and month
tk.Label(root, text="Year:").pack(pady=5)
year_entry = tk.Entry(root)
year_entry.pack(pady=5)

tk.Label(root, text="Month:").pack(pady=5)
month_entry = tk.Entry(root)
month_entry.pack(pady=5)

# Button to display the calendar
show_button = tk.Button(root, text="Show Calendar", command=show_calendar)
show_button.pack(pady=10)

# Text widget to display the calendar
calendar_display = tk.Text(root, width=20, height=8, font=("Courier", 12))
calendar_display.pack(pady=10)
calendar_display.config(state="disabled")  # Set to read-only

# Run the main application loop
root.mainloop()

Explanation

1. Import Required Libraries:
   • tkinter: Used to create the GUI components.
   • calendar: Provides functions to generate text-based calendars.
2. Define show_calendar Function:
   • This function generates and displays the calendar for a specified month and year.
   • Get User Input:
     • year = int(year_entry.get()): Retrieves and converts the entered year from the year_entry field.
     • month = int(month_entry.get()): Retrieves and converts the entered month from the month_entry field.
   • Generate Calendar Text:
     • cal_text = calendar.month(year, month): Generates a text-based calendar for the specified year and month using the calendar.month function, which returns a string containing the formatted calendar.
   • Display Calendar in the Text Widget:
     • calendar_display.config(state=”normal”): Sets the Text widget to be editable so we can update it.
     • calendar_display.delete(“1.0”, tk.END): Clears any previous calendar from the display.
     • calendar_display.insert(tk.END, cal_text): Inserts the generated calendar text into the Text widget.
     • calendar_display.config(state=”disabled”): Sets the Text widget to read-only after updating to prevent user modification.
   • Error Handling:
     • If the user enters non-numeric values for year or month, a ValueError is raised, and an error message is displayed instead of the calendar.
3. Initialize the Main Application Window:
   • root = tk.Tk(): Creates the main application window.
   • root.title(“Calendar Viewer”): Sets the title of the window to “Calendar Viewer”.
   • root.geometry(“300×300”): Sets the window size to 300×300 pixels.
4. Create Labels and Entry Fields for Year and Month:
   • tk.Label(root, text=”Year:”) and year_entry = tk.Entry(root): A label and entry field for entering the year.
   • tk.Label(root, text=”Month:”) and month_entry = tk.Entry(root): A label and entry field for entering the month.
   • .pack(pady=5): Adds some vertical padding to space out the elements.
5. Create “Show Calendar” Button:
   • show_button = tk.Button(root, text=”Show Calendar”, command=show_calendar): A button labeled “Show Calendar” that calls show_calendar when clicked.
6. Text Widget to Display the Calendar:
   • calendar_display = tk.Text(…): Creates a Text widget to display the calendar output.
   • width=20 and height=8: Set the size of the widget to display the calendar text without scrollbars.
   • font=(“Courier”, 12): Sets the font to Courier to ensure the calendar text is displayed in a monospaced font, aligning columns properly.
   • calendar_display.config(state=”disabled”): Initially sets the Text widget to read-only.
7. Run the Main Event Loop:
   • root.mainloop(): Starts the tkinter main event loop, which keeps the application window open and responsive to user actions.

Sample Usage

1. Enter Year and Month:
   • The user enters the desired year (e.g., 2024) and month (e.g., 11 for November).
2. Show Calendar:
   • Clicking “Show Calendar” generates and displays the calendar for November 2024.
3. Display Calendar:
   • The Text widget displays the formatted calendar for the selected month and year.

Sample Output

If the user enters Year: 2024 and Month: 11, the output in the Text widget might look like this:

   November 2024
Mo Tu We Th Fr Sa Su
             1  2  3
 4  5  6  7  8  9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30

Notes

• Error Handling: If the user enters an invalid year or month, a message is displayed to prompt for correct input.
• Monospaced Font: The Courier font ensures that each character has the same width, aligning the calendar columns correctly.

Summary

This Python program provides a simple, GUI-based calendar viewer using tkinter.

It allows users to input a year and month and then displays the corresponding calendar using Python’s calendar module.

The program handles basic errors and ensures correct formatting for the calendar output.