Tkinter Checkbutton initialization problem

[Paul Rubin]

Python 2.4, Windows XP. If I say:

f = Frame()
f.grid()
v = IntVar()
c = Checkbutton(f, text='hi there', variable=v)
c.grid()
f.mainloop()

then the checkbutton should initially display as being checked.
But it doesn't. It shows up unchecked, even though v.get() returns 1.
The select operation DOES update the display if there's no variable.

It works properly under Linux with (I think) Python 2.3. I don't have
a 2.4.1 Windows installation to try right now.

Is this a known bug? Is it fixed in 2.4.1? Is there a simple
workaround, that lets me initialize a checkbutton and still be able to
read its state?

Thanks.

 

[Scott David Daniels]

Python 2.4, Windows XP. If I say:
f = Frame()
f.grid()
v = IntVar()

v.set(1) # Might help. v.get() at this point returned 0 for me.

 

[Paul Rubin]

v.set(1) # Might help. v.get() at this point returned 0 for me.

Yeah, I tried that too. Further reorganization of the code in some
other way suddenly made it start working. I'll have to examine it to
see what I did since I wasn't paying attention to that particular
problem at the time. I had checked sf.net for a bug report on this
and didn't see one, but maybe didn't check carefully enough. I'll
look a little more and then file one, I guess.

 

[Eric Brunel]

Python 2.4, Windows XP. If I say:

f = Frame()
f.grid()
v = IntVar()
c = Checkbutton(f, text='hi there', variable=v)
c.grid()
f.mainloop()

then the checkbutton should initially display as being checked.
But it doesn't. It shows up unchecked, even though v.get() returns 1.
The select operation DOES update the display if there's no variable.

In tcl/tk, booleans are not integers. So using an IntVar to represent something which is basically a boolean will cause unexpected behaviors like the one you're experiencing here. Just do:

....
v = BooleanVar()
v.set(1)
....

and everything should be fine.

HTH