10. Modify via radiobutton

See: https://www.geeksforgeeks.org/python-setting-and-retrieving-values-of-tkinter-variable/
See: https://dafarry.github.io/tkinterbook/tkinter-events-and-bindings.htm
See: https://python-course.eu/tkinter/variable-classes-in-tkinter.php
../_images/modify_via_radiobutton.png

10.1. Required Syntax

class StringVar
Syntax: text_var = tk.StringVar()
Description: Creates a Tkinter variable for holding string data.
Default: None
Example: text_var = tk.StringVar()
get()
Syntax: current_value = text_var.get()
Description: Retrieves the current value of the StringVar.
Default: None
Example: current_value = text_var.get()
set()
Syntax: text_var.set("New Value")
Description: Sets the value of the StringVar to the specified string.
Default: None
Example: text_var.set("black")
variable
Syntax: widget = tk.Radiobutton(parent, text="label", variable=variable, command=callback_function)
Description: Associates a Tkinter variable with the Radiobutton state.
Default: None
Example: blue_radiobutton = tk.Radiobutton(root, text="Blue Label", variable=color_var, value="blue", command=set_label_color)
command
Syntax: button_widget = tk.BuRadiobuttontton(parent, command=callback_function)
Description: Specifies the function to be called when the Radiobutton is clicked.
Default: None
Example: button_widget = tk.Radiobutton(root, command=on_click)

10.1.1. Code example

import tkinter as tk


# Function to set the label color
def set_label_color():
    label.config(fg=color_var.get())


# Create the main window
root = tk.Tk()
root.geometry("400x150")
root.title("Modify via Radiobutton Example")

# Create a StringVar to hold the color value
color_var = tk.StringVar()
color_var.set("black")  # Initial value

# Create Radiobuttons to toggle the label color using the color as value
blue_radiobutton = tk.Radiobutton(root, text="Blue Label", variable=color_var, value="blue", command=set_label_color)
blue_radiobutton.grid(row=0, column=0, padx=10, pady=5, sticky="w")

green_radiobutton = tk.Radiobutton(root, text="Green Label", variable=color_var, value="green", command=set_label_color)
green_radiobutton.grid(row=1, column=0, padx=10, pady=5, sticky="w")

red_radiobutton = tk.Radiobutton(root, text="Red Label", variable=color_var, value="red", command=set_label_color)
red_radiobutton.grid(row=2, column=0, padx=10, pady=5, sticky="w")

# Create a Label widget
label = tk.Label(root, text="Sample Text", font=("Helvetica", 16), fg="black")
label.grid(row=0, column=1, rowspan=3, padx=10, pady=20)

# Run the application
root.mainloop()