Hi Michael,
> The problem is apparently that the widget name of the menu's "button" is
> assigned by Tk and there does not seem to be a way to access this subwidget
> from within Tkinter. Besides this I don't understand why this does not happen
> with the context
menu from my previous example but only with a cascaded menu.
Your example fails for both context and cascading menus under 32-bit
Python 2.7 for Windows.
I appreciate your and Michael's help. Thank you both!
Malcolm
<snipped>
Thus spoketh "Michael O'Donnell" <michael.odonn...@uam.es>
unto us on Sun, 21 Nov 2010 10:26:24 +0100:
> Hi Malcom,
>
> Change your statusbarUpdate for the following, which will print out
> the index of the currently selected menu item:
>
> def statusbarUpdate( event=None ):
> print tk.call(event.widget, "index", "active")
>
> Note that this uses tcl/tk code, where Tkinter code should be used,
> but it seems the corresponding tkinter code is broken, e.g., with
>
> def statusbarUpdate( event=None ):
> print popup.index('active')
>
> ...always returns None on changing the menu selection.
I believe this is because the button in the menu is treated as a
different
widget by Tk, so the correct call would be:
def statusbarUpdate(event):
print event.widget.index('active')
However, using this I get an error:
Exception in Tkinter callback
Traceback (most recent call last):
File "/usr/local/lib/python2.6/lib-tk/Tkinter.py", line 1410, in
__call__ return self.func(*args)
File "test2.py", line 18, in statusbarUpdate
print event.widget.index('active')
ValueError: substring not found
This is apparently because event.widget is not (as expected) a widget
instance but a string which looks like .#153369036.#153369036#153369644
Trying to feed this string to nametowidget() I get the following error:
Exception in Tkinter callback
Traceback (most recent call last):
File "/usr/local/lib/python2.6/lib-tk/Tkinter.py", line 1410, in
__call__ return self.func(*args)
File "test2.py", line 18, in statusbarUpdate
print tk.nametowidget(event.widget)#.index('active')
File "/usr/local/lib/python2.6/lib-tk/Tkinter.py", line 1079, in
nametowidget w = w.children[n]
KeyError: '#153369036'
The problem is apparently that the widget name of the menu's "button" is
assigned by Tk and there does not seem to be a way to access this
subwidget from within Tkinter.
Besides this I don't understand why this does not happen with the
context
menu from my previous example but only with a cascaded menu.
This looks to me like a bug in Tkinter, but I don't have an idea how
this
could ever be fixed (at least without dealing with _tkinter's
internals),
so we probably will have to stick with Michael's workaround.
</snipped>
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