Assuming the following code has been written:
self.firstRadioButton = Radiobutton(self.__canvas, text="ONE", fg=\'white\', bg=BACKGROUND_COLOR, vari
The key is to make sure that both radiobuttons share the same variable. Then, to know which one is selected you simply need to get the value of the variable.
Here is an example:
import tkinter
# function that is called when you select a certain radio button
def selected():
print(var.get())
root = tkinter.Tk()
var = tkinter.StringVar() #used to get the 'value' property of a tkinter.Radiobutton
# Note that I added a command to each radio button and a different 'value'
# When you press a radio button, its corresponding 'command' is called.
# In this case, I am linking both radio buttons to the same command: 'selected'
rb1 = tkinter.Radiobutton(text='Radio Button 1', variable=var,
value="Radio 1", command=selected)
rb1.pack()
rb2 = tkinter.Radiobutton(text='Radio Button 2', variable=var,
value="Radio 2", command=selected)
rb2.pack()
root.mainloop()