[Kmymoney-devel] setUpdatesEnabled again

[Alvaro Soliverez]

On Sun, Aug 16, 2009 at 3:09 AM, Cristian Oneţ <onet.cristian at gmail.com>wrote:

> On Sun, Aug 16, 2009 at 3:12 AM, Alvaro Soliverez<asoliverez at gmail.com>
> wrote:
> > Hello all,
> > I ran into the setUpdatesEnabled problem again.
> >
> > In the kbudgetview, both lists there call setUpdatesEnabled(false), fill
> in
> > the contents, then call setUpdatesEnabled(true) and repaintContents().
> If you try leaving the setUpdatesEnabled calls but instead of
> repaintContents() you use updateContents() what happens?


updateContents() is protected. I tried update() instead, but no luck.


> The Qt doc
> suggests that calling repaint() (which repaintContents() does)
> directly is not recommended and instead update() should be called
> because "...is better, as it permits Qt to optimize for speed and
> minimize flicker". But calling setUpdatesEnabled(true) implicitly
> calls update on the widget so maybe repaintContents() or
> updateContents() should not be used. This can be seen in the
> difference between:
> http://doc.trolltech.com/3.3/qwidget.html#updatesEnabled-prop
> http://doc.trolltech.com/4.5/qwidget.html#updatesEnabled-prop
> The qt3 example has a repaint after setUpdatesEnabled(true) while the
> qt4 example doe not have anything after setUpdatesEnabled(true).
>

Yes, I tried also without anything after setUpdatesEnabled. And you are
right, we should remove the repaintContents because it is supposed to call
update() anyway.


>
> > Both lists don't show on the screen until I click on a column or an item.
> If
> > I remove the setUpdatesEnabled call, they work fine.
> >
> > I thought it might be that a parent widget might be calling it too, but
> my
> > search returned empty.
> > Do you know where the problem might be?
> >
> > I think this might be the same problem that the accounts and categories
> > views are having.
> Another thing caught my attention in the difference between the
> documentation in qt3 and qt4 of the updatesEnabled property. In qt4 it
> is mentioned that "In Qt, widgets normally do not generate screen
> flicker, but on X11 the server might erase regions on the screen when
> widgets get hidden before they can be replaced by other widgets.
> Disabling updates solves this.". But this was not mentioned in the qt3
> doc so my suggestion would be to remove the calls to setUpdatesEnabled
> and add them only in places where we observe that it is really
> necessary.
>
> Regards,
> Cristian
>
> P.S: I don't have access to my development environment above I was
> just guessing, sorry if it's only noise
>

Your comments match what I see. So far, removing the call makes it work
better. I guess that for some cases, like the register, we will have to deal
with it. But in most cases, with only a couple of dozen items at most, we
can do without  setUpdatesEnabled, at least for now.
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