Please help -- Tkinter Scale widget with DoubleVar is acting weird
Jared.Cohen at noaa.gov
Thu Aug 19 17:32:56 CEST 2004
Hi all. I'm currently using a Tkinter Scale widget which uses a
DoubleVar as its control variable. I then use the "trace_variable('w',
callback)" method to invoke a callback whenever the DoubleVar changes.
The problem is this: the callback is triggered when the slider moves (as
it should), but it's also triggered when I just HOVER the mouse over the
slider without clicking! Somehow or other, it must think that the
control variable is being changed, even though it isn't. I *think* that
this problem is related to the loss of precision that DoubleVars can
have, but I'm not really sure. Has anyone else experienced this problem?
How can I fix this?
As an aid, here's a quick stub program that illustrates the problem. Try
(for example) moving the slider to 0.3, release the mouse button, then
move the mouse pointer back and forth over the slider WITHOUT clicking.
Each time the pointer passes over the slider, it will print the value.
import sys, Tkinter, types
root = Tkinter.Tk()
var = Tkinter.DoubleVar()
slider = Tkinter.Scale(root,
from_ = 0.0,
to = 1.0,
resolution = 0.1,
variable = var,
orient = 'horizontal')
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