[Tutor] Tkinter - Destroying windows, destroying widgets

[Glen Wheeler]

  Thanks alot Mike and Rick - yet again the secret key to all my problems
lies in classes :)

  I already had to convert almost everything into classes - seems as though
I've got to do the lot.

  Thanks alot,
  Glen (busily converting python code)

----- Original Message -----
From: Michael P. Reilly <arcege@shore.net>
To: Glen Wheeler <wheelege@tsn.cc>
Cc: <tutor@python.org>
Sent: Monday, February 05, 2001 1:00 AM
Subject: Re: [Tutor] Tkinter - Destroying windows, destroying widgets


> >
> > This is a multi-part message in MIME format.
> >
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> >
> >   Hey all,
> >
> >   I was just writing up a little tkinter app (a game, actually) and I =
> > have hit a wall.  My predicament, is that I want to destroy an object =
> > (right word?) but I want to do it in a function...for example in this =
> > code :
> >
> > from Tkinter import *
> >
> > def die():
> >     l.destroy() ## here is the problem - root.l.destroy() does not work
=
> > either - I think since variables are local in functions it doesn't have
=
> > any clue as to the existence of the label "l"
> >     print 'yo'    =20
> >     raw_input("hi")
> >
> > root =3D Tk()
> > root.title('jim')
> > l =3D Label(root, text=3D'hi im root').pack()
> > second =3D Toplevel(root)
> > b =3D Button(root, text=3D'yo', command=3Ddie).pack()
> >
> > mainloop()
> >
> >   No matter how hard I try I cannot kill the label "l" using the button,
=
> > and have it do other things as well.  Say I wanted to destroy a widget =
> > in a different window??  That label is in the same toplevel.  I just =
> > know there is a way to say something akin to "In the widget 'root' is a
=
> > widget 'l' - kill it" but for the life of me I cannot find it.  You =
> > can't pass a widget as an argument using lambda, either - I tried tho :)
> >   I've looked in John Grayson's book and the python docs but I can't =
> > find anything.  Help!
>
> You have the right idea, but if you print "l", it is set to None, not
> to an object.  That is because the pack() method returns None.  You
> will want to use:
>   l = Label(root, text = 'hi im root')
>   l.pack()
>
> I would suggest however, creating a class (often a subclass of Frame)
> to represent what you want, setting attributes for the widgets that you
> wish to access later:
>
>   class SpamEggs(Frame):
>     def __init__(self, master=None, labeltxt='', buttontxt=''):
>       Frame.__init__(self, master)
>       self.l = Label(self, text=labeltxt)
>       self.b = Button(self, text=buttontxt, command=self.die)
>       self.l.pack()
>       self.b.pack()
>     def die(self):
>       if self.l:
>         self.l.destroy()
>       self.l = None # so we do not destroy it twice
>
>   root = Tk()
>   SpamEggs(root, 'hi im root', 'yo').pack()
>   root.mainloop()
>
> Good luck,
>   -Arcege
>
> --
> ------------------------------------------------------------------------
> | Michael P. Reilly, Release Manager  | Email: arcege@shore.net        |
> | Salem, Mass. USA  01970             |                                |
> ------------------------------------------------------------------------
>
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