Getting Tkinter Text contents before destruction

[Bob Greschke]

Hi!

I want to grab the contents of a Text widget when the frame it's on gets
destroyed. I tried TextWidget.bind ("<Destroy>" ... , but the widget is gone
before the call gets made, and I'd really hate to do something with the
function that gets called with TextWidgetsFram e.bind("<Destro y>", ..., since
that one function handles all of the frames in the program...or would that
even work?

How can I do this?

Thanks!

Bob

[James Stroud]

Re: Getting Tkinter Text contents before destruction

Bob Greschke wrote:[color=blue]
> Hi!
>
> I want to grab the contents of a Text widget when the frame it's on gets
> destroyed. I tried TextWidget.bind ("<Destroy>" ... , but the widget is gone
> before the call gets made, and I'd really hate to do something with the
> function that gets called with TextWidgetsFram e.bind("<Destro y>", ..., since
> that one function handles all of the frames in the program...or would that
> even work?
>
> How can I do this?
>
> Thanks!
>
> Bob
>
>[/color]

If TextWidgetsFram e inherets from frame, you can override the destroy()
method which gets called when the parent gets destroyed. Or
alternatively, you can override the __del__ function, which gets called
when the reference count goes to 0:


py> from Tkinter import *
py> tk = Tk()
py> class F(Frame):
.... def destroy(self):
.... print 'bob'
.... Frame.destroy(s elf)
....
py> f = F(tk)
py> f.pack()
py> tk.destroy()
bob

James

[Eric Brunel]

Re: Getting Tkinter Text contents before destruction

On Mon, 06 Feb 2006 19:32:52 -0800, James Stroud <jstroud@ucla.e du> wrote:[color=blue]
> If TextWidgetsFram e inherets from frame, you can override the destroy()
> method which gets called when the parent gets destroyed.[/color]

Unfortunately, it doesn't get called. Everything actually happens at tk
level, where the destroy *command* gets called, but doesn't inform the
Python interface object. The destroy method is only a way to call tk's
destroy command, but overloading it has an effect only when called from
Python, not from the underlying tk layer.
--
python -c "print ''.join([chr(154 - ord(c)) for c in
'U(17zX(%,5.zmz 5(17;8(%,5.Z65\ '*9--56l7+-'])"

[Eric Brunel]

Re: Getting Tkinter Text contents before destruction

On Mon, 6 Feb 2006 20:11:28 -0700, Bob Greschke <bob@greschke.c om> wrote:
[color=blue]
> Hi!
>
> I want to grab the contents of a Text widget when the frame it's on gets
> destroyed. I tried TextWidget.bind ("<Destroy>" ... , but the widget is
> gone
> before the call gets made, and I'd really hate to do something with the
> function that gets called with TextWidgetsFram e.bind("<Destro y>", ...,
> since
> that one function handles all of the frames in the program...or would
> that
> even work?
>
> How can I do this?[/color]

One way is to define the deletion callback for the text's parent window to
get the text before the widget gets deleted. To do that, you can use
text.winfo_topl evel() to get the parent Toplevel for your text widget,
then define the callback via wdw.protocol('W M_DELETE_WINDOW ', ...). Here
is a detailed example:

-----------------------------------------------------
from Tkinter import *

root = Tk()

txt = None

def openWdw():
global txt
wdw = Toplevel()
frm = Frame(wdw)
frm.pack(expand =1)
txt = Text(frm)
txt.pack()
print txt.winfo_tople vel(), frm, root
txt.winfo_tople vel().protocol( 'WM_DELETE_WIND OW', getText)

def getText():
print txt.get(1.0, END)
txt.winfo_tople vel().destroy()

Button(root, text='Go', command=openWdw ).pack()

root.mainloop()
-----------------------------------------------------

This will of course only work if the only reason for which the text widget
can be destroyed is if its parent window is closed.

HTH
--
python -c "print ''.join([chr(154 - ord(c)) for c in
'U(17zX(%,5.zmz 5(17;8(%,5.Z65\ '*9--56l7+-'])"

[Fredrik Lundh]

Re: Getting Tkinter Text contents before destruction

Bob Greschke wrote:
[color=blue]
> I want to grab the contents of a Text widget when the frame it's on gets destroyed. I tried
> TextWidget.bind ("<Destroy>" ... , but the widget is gone before the call gets made, and I'd really
> hate to do something with the function that gets called with TextWidgetsFram e.bind("<Destro y>",
> ..., since that one function handles all of the frames in the program...or would that even work?
>
> How can I do this?[/color]

in what ways can the frame be destroyed ?

assuming that you're talking about user-initiated actions, the most reasonable way
to do this is to implement a WM_DELETE_WINDO W handler on the toplevel
window that the frame is located in, and deal with the text widget in there. see:

http://effbot.org/tkinterbook/tkinter-events-and-bindings.htm#protocols

</F>