10 May
2003
10 May
'03
8:47 a.m.
On Fri, May 09, 2003 at 11:46:33PM +0200, Matthias
Kretz wrote:
Content-Description: signed data
here's a question to ask of a toolkit: can i set the depressed/raised
state of a button programmatically, without implying that the user
clicked it?
if the answer is yes, then chances are you are using a toolkit in
which MVC will be fairly easy to implement. if no, then chances are
its going to be a pain.
then ask the same question of value indicator widgets. etc.
yes, its a widely known moniker, but its not a widely used practice. i
know that in GTK+, you have to basically be willing to tolerate
feedback loops between the model and the view, so that when one is
changed, the other gets changed, which might change the first one
again, etc. heaven help you if you suffer from rounding issues between
the model and the view, because then you have no way to stop the loop
without a deadful kludge. without rounding issues, you have to do lots
of this sort of thing:
handler_for_some_gui_event (...) {
if (state_of_view != state_of_model) {
change_view ();
}
}
i've rarely seen code that looks like this when i look at open source
software. maybe i'm looking for the wrong thing.
--p
When I was listening to your talk and about the
MVC part I was pretty
surprised since it was one of the first things I learned when reading about
Qt/KDE programming. I was under the impression, that everyone would be using
it...
Yup, its like page 2 of design patters or something.