Am 24.05.23 um 03:18 schrieb Rob Cliffe:
I have recently started converting a large project to tkinter, starting
with zero knowledge of tkinter. (You are free to think: BAD IDEA. 😁)
Welcome to the awesome world of GUI development.
I was writing a subclass of the Checkbutton class (tkinter's name
for what I call a checkbox). I needed to be able to (1) set (2) clear
(3) interrogate the checked state. This is easy to do if you associate
a "variable" with each Checkbutton instance, as seems to be usual
tkinter practice. ("variable" is not a variable in the usual sense, but
an object provided by tkinter that is linked to a GUI object (such as a
Checkbutton), so that when the GUI object changes, the value of the
"variable" changes, and vice versa.) However, I decided that I wanted to
dispense with the variable, if possible.
As you found out the hard way, it is possible, but then you dive into
the internals of how the widgets work - usually you don't want to know
that. Also, this bit differs between Tk and Ttk widgets.
[...] lengthe description of Checkbutton internals
In GUI programming, you will meet a bag of concepts that you haven't
seen in sequential programming before. To make it worse, every GUI
toolkit brings its own new set of concepts to the table. Maybe it is
helpful to work through a Tk tutorial first. This is a good one:
http://tkdocs.com/tutorial/index.html
Similarly to the tutorial I would suggest to stick with the ttk widgets.
Those are an "update" (> 10 years ago) to the tk widgets and are
supposed to provide sensible defaults matching the users experience with
native GUI elements. There are only 3 widgets where you must use a Tk
widget, this is Text (for multiline formatted text entry), Canvas (for
2D drawings), and Toplevel (for new windows/ popups etc.)
Christian
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