Tkinter

[Scott David Daniels]

Luke wrote:
> Hello, I'm an inexperienced programmer and I'm trying to make a
> Tkinter window and have so far been unsuccessful in being able to
> delete widgets from the main window and then add new ones back into
> the window without closing the main window.
> 
> The coding looks similar to this:
> ...
> from Tkinter import *
> def MainWin():
>     main=Tk()
>     ...
>     close_frame1=Button(frame1,text='close',bg='light gray',
> command=frame1.destroy)
>     close_frame1.pack_propagate(0)
>     close_frame1.pack(side=TOP, anchor=N,pady=25)
>     if frame1.destroy==True:
>         frame1=Frame(back_ground,width=213,height=480,bg='white')
>         frame1.pack_propagate(0)
>         frame1.pack(side=TOP,anchor=N)
>     main.mainloop()
> MainWin()
> 
> It may just be bad coding but either way I could use some help.


I'll tell you what I find helps me in exploring Tkinter: running
Idle in the "no-subprocesses" mode.  Now the resulting system _is_
less stable and may well require you to restart from time to time,
but there is a compensation: you can see the effect of each
operation as you do it by hand, as well as checking expressions:

If in Windows:
     run cmd
     C:\> python -m idlelib.idle -n

If in Linux / MacOSx:
     Start a terminal:
     $ python  -m idlelib.idle -n &

Once idle shows up,
     >>> import Tkinter
     >>> main = Tkinter.Tk()
<a window shows up>
       ...

Following through your code, you'll see you start the frame,
add the button, and, immediately after getting everything set
up, you check:
 >     if frame1.destroy==True:
Which it will never be (frame1.destroy is a method, not data).
Once you get the base set up, your code should runfrom events.

So, to get a single step farther:
At the top of the MainWin function, insert:
     global frame1, close_frame1
Replace your "close_frame1 =" line down to end-o-function with:
     def on_click():
         global frame1, close_frame1
         frame1.destroy()
         frame1 =Frame(back_ground,width=213,height=480,bg='white')
         frame1.pack_propagate(0)
         frame1.pack(side=TOP,anchor=N)
         close_frame1 = Button(frame1,text='retry', bg='light blue',
                               command=on_click)
         close_frame1.pack_propagate(0)
         close_frame1.pack(side=TOP, anchor=N,pady=25)
     close_frame1 = Button(frame1,text='close',bg='light gray',
                                     command=on_click)
     close_frame1.pack_propagate(0)
     close_frame1.pack(side=TOP, anchor=N,pady=25)

The "global" lines are needed so that on_click and MainWin (which both
set the two names) are talking about the same objects.

--Scott David Daniels
Scott.Daniels at Acm.Org