Hi all,
I've just started trying to learn how to use ttk, and I've discovered
something that I don't understand. I'm using Python 3.3.0 in Linux Mint
15. Suppose I create the following module:
# begin tkderp.py
import tkinter as tk
import tkinter.messagebox as _
from tkinter import ttk
from imp import reload
_root = tk.Tk()
_root.withdraw()
def f():
style = ttk.Style(_root)
style.theme_create('newtheme', parent = 'default')
tk.messagebox.showwarning('test', 'test')
style.theme_use('newtheme')
tk.messagebox.showwarning('test', 'test')
# end tkderp.py
The function f() is supposed to spawn two warning dialogs. AIUI, the
"style.theme.use('newtheme')" line shouldn't make any difference - it
would refresh any existing ttk widgets and alter the appearance of any
subsequently created ones if I had changed any of the new theme's
settings, but in the above context nothing it does should be discernible
to the user. If I try to call f() the first warning gets shown, but the
second one causes an exception:
Python 3.3.1 (default, Apr 17 2013, 22:30:32)
[GCC 4.7.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tkderp
>>> tkderp.f()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/phil/Python/tkderp.py", line 17, in f
tk.messagebox.showwarning('test', 'test')
File "/usr/lib/python3.3/tkinter/messagebox.py", line 87, in showwarning
return _show(title, message, WARNING, OK, **options)
File "/usr/lib/python3.3/tkinter/messagebox.py", line 72, in _show
res = Message(**options).show()
File "/usr/lib/python3.3/tkinter/commondialog.py", line 48, in show
s = w.tk.call(self.command, *w._options(self.options))
_tkinter.TclError: unknown color name ""
If I try reloading the module and calling the function again, this time
the first of the two warnings raises the exception. Since I don't really
understand how the ttk.Style class works, I can't say whether this
behaviour is expected or not. But here's what's weird. Suppose that I
comment out the last two lines in the definition of f(), like so:
# begin modified tkderp.py
import tkinter as tk
import tkinter.messagebox as _
from tkinter import ttk
from imp import reload
_root = tk.Tk()
_root.withdraw()
def f():
style = ttk.Style(_root)
style.theme_create('newtheme', parent = 'default')
tk.messagebox.showwarning('test', 'test')
#style.theme_use('newtheme')
#tk.messagebox.showwarning('test', 'test')
# end modified tkderp.py
Unsurprisingly, importing the module and calling f() displays a single
warning dialog and raises no exception. If I then uncomment those two
lines, reload the module and call f() again (by entering
tkderp.reload(tkderp).f()), the function works like it was supposed to
in the first place: two warnings, no exceptions. I can reload the module
as many times as I like and f() will continue to work without any problems.
On Windows 7 (sys.version is '3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012,
10:57:17) [MSC v.1600 64 bit (AMD64)]') there's no problem; f() works
fine in the first place. Does anybody know what's going on?
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