Need help with Tkinter

[Fredrik Lundh]

rodzilla2000 at my-deja.com wrote:
> Change the "Hello World" button a "Add Exit Button" that would put
> another button on the screen to allow exiting the program.
> 
> Add the additional exit button...
> 
> Here's the code:
> 
> =========START OF CODE
> # Button test...
> 
> import sys
> from Tkinter import *
> 
> #main routine
> def main():
>     root=Tk()
>     btnAddButton=Button(root)
>     btnAddButton['text']='Add Exit Button'
>     btnAddButton['command']=subAddButton(root)   # See below

this *calls* the subAddButton, and assigns the return
value as the button command.  Tkinter should really
complain about that, but it doesn't -- after all, your
function might be returning a valid Tcl command...

try changing:

>     btnAddButton['command']=subAddButton(root)   # See below


to:

    def cb(root=root):
        subAddButton(root)

    btnAddButton['command'] = cb

also consider using keyword syntax to initialize the widgets.  see 
http://www.pythonware.com/library/tkinter/introduction/widget-configuration.htm
for more info.

>     btnAddButton.pack()
> 
>     #start mainloop
>     root.mainloop
> 
> def subAddButton(parent):
>     btnExitButton=Button(parent)
>     btnExitButton['text']='Exit Program'
>     btnExitButton['command']=subExit   #see below
>     btnExitButton.pack()
> 
> def subExit():
>     sys.exit(0)
> 
> 
> #execute the main routine
> main()

</F>