# This program demonstrates a group of Checkbutton widgets.

import Tkinter
import tkMessageBox

class MyGUI:
    def __init__(self):
        # Create the main window.
        self.main_window = Tkinter.Tk()

        # Create two frames. One for the checkbuttons
        # and another for the regular Button widgets.
        self.top_frame = Tkinter.Frame(self.main_window)
        self.bottom_frame = Tkinter.Frame(self.main_window)
        
        # Create three IntVar objects to use with
        # the Checkbuttons.
        self.cb_var1 = Tkinter.IntVar()
        self.cb_var2 = Tkinter.IntVar()
        self.cb_var3 = Tkinter.IntVar()
        
        # Set the intVar objects to 0.
        self.cb_var1.set(0)
        self.cb_var2.set(0)
        self.cb_var3.set(0)
        
        # Create the Checkbutton widgets in the top_frame.
        self.cb1 = Tkinter.Checkbutton(self.top_frame, \
                    text='Option 1', variable=self.cb_var1)
        self.cb2 = Tkinter.Checkbutton(self.top_frame, \
                    text='Option 2', variable=self.cb_var2)
        self.cb3 = Tkinter.Checkbutton(self.top_frame, \
                    text='Option 3', variable=self.cb_var3)

        # Pack the Checkbuttons.
        self.cb1.pack()
        self.cb2.pack()
        self.cb3.pack()

        # Create an OK button and a Quit button.
        self.ok_button = Tkinter.Button(self.bottom_frame, \
                      text='OK', command=self.show_choice)
        self.quit_button = Tkinter.Button(self.bottom_frame, \
                      text='Quit', command=self.main_window.destroy)

        # Pack the Buttons.
        self.ok_button.pack(side='left')
        self.quit_button.pack(side='left')

        # Pack the frames.
        self.top_frame.pack()
        self.bottom_frame.pack()
        
        # Start the mainloop.
        Tkinter.mainloop()

    # The show_choice method is the callback function for the
    # OK button.
    
    def show_choice(self):
        # Create a message string.
        self.message = 'You selected:\n'

        # Determine which Checkbuttons are selected and
        # build the message string accordingly.
        if self.cb_var1.get() == 1:
            self.message = self.message + '1\n'
        if self.cb_var2.get() == 1:
            self.message = self.message + '2\n'
        if self.cb_var3.get() == 1:
            self.message = self.message + '3\n'

        # Display the message in an info dialog box.
        tkMessageBox.showinfo('Selection', self.message)

def main():
   # Create an instance of the MyGUI class.
   my_gui = MyGUI()

main()