[Development] QWidget mouse events - different order

[Martin Koller]

On Friday 20 December 2013 08:31:24 Martin Koller wrote:
> On Thursday 19 December 2013 09:19:38 Rick Stockton wrote:
> > On 12/18/2013 01:10 PM, Andreas Aardal Hanssen wrote:
> > > On 18 Dec 2013, at 22:07, Rayner Pupo Gómez <rpgomez at uci.cu> wrote:
> > Inner-most quote is from Martin Koller.
> > 
> > >>> I've discovered that with Qt5 I get a different order of mouse events on
> > >>> a QWidget than with Qt4 (openSuse 13.1 Linux, X11):
> > >>> double clicking a widget results in Qt4 in:
> > >>> mousePressEvent 
> > >>> mouseReleaseEvent 
> > >>> mouseDoubleClickEvent 
> > >>> mousePressEvent 
> > >>> mouseReleaseEvent
> > >>> but in Qt5 in:
> > >>> mousePressEvent 
> > >>> mouseReleaseEvent 
> > >>> mousePressEvent 
> > >>> mouseDoubleClickEvent 
> > >>> mouseReleaseEvent 
> > >>> I tested with Qt4.8.5 and Qt5.2.
> > >>> Is this behavioral change intended, undefined, a bug ?
> > >>> (it results in my app not behaving as before ...)
> > >> I think it's a mistake to rely on the order of this kind of events, there are 
> > >> fired asynchronously, your logic cant depend on this
> > > Wrong! The order is very essential and can and must be relied on.
> > > The behaviour in Qt 5 is questionable. I believe the double-click must come first to be able to distinguish from two presses.
> > >
> > > I also wonder if it's accurate / true that Qt 4 sends the second press after the double-click. AFAIR:
> > >
> > > Press
> > > Release
> > > DoubleClick
> > > Release
> > >
> > > Is the right events for double-clicking.
> > >
> > > Andreas
> > Andreas, I'm confirming the QT5 behavior, to be as Martin describe. BUT,
> > the Qt4 behavior seems to be as YOU recall - no ButtonPress" at all for
> > the fast-enough second click which invoked a "DoubleClick event.
> 
> I'm not making things up. This is what my testprogram gives.
> I attach it here.

I see now the problem with my testprogram.
I also called the basclass implementation, which leads to the extra mousePressEvent.
(fixed prog attached)

when I just print the events in my implementation, I get:
Qt4:
mousePressEvent
mouseReleaseEvent
mouseDoubleClickEvent
mouseReleaseEvent

Qt5:
mousePressEvent
mouseReleaseEvent
mousePressEvent
mouseDoubleClickEvent
mouseReleaseEvent

so it's just the extra mousePressEvent in Qt5 which is wrong.

-- 
Best regards/Schöne Grüße

Martin
A: Because it breaks the logical sequence of discussion
Q: Why is top posting bad?

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