QtWebEngine duplicate touch events

ageblade

Hi,
I have a problem with touch events using a QWebEngineView within my QApplication.
When i click on a button in my web page it is double clicked by Qt for some reason, when i open the same page in Chrome this behavior is not happening.

Did someone else bumped into this ? Is there any known solution ?

Thanks, Idan

Update:

Tried the attributes:
WA_AcceptTouchEvents
WA_TouchPadAcceptSingleTouchEvents
AA_SynthesizeMouseForUnhandledTouchEvents
AA_SynthesizeTouchForUnhandledMouseEvents

But none of them works for this issue.

gladiatorchirag

I am facing the same issue. Tried everything but no success yet.

Related bug:
https://bugreports.qt.io/browse/QTBUG-39814

ageblade

Hi,
I managed to overcome this bug using a QEventFilter and filtering mouse events on the widget and it's children. I will post the code soon.

However if you need both your mouse events and touch events handled this is not the solution for you, but maybe a good start.

gladiatorchirag

Thanks "ageblade". Kindly post the code soon. This has become a bottleneck for me....

ageblade

Hi, sorry for the delay.. but here it is!

This is the code initializing the view in the main function:

@
QWebEngineView view;
view.load(url);
view.show();

for (int i = 0; i < view.children().size(); i++)
{
QObject *child = view.children().at(i);
child->installEventFilter(new QMouseEventFilter);
}
@

and QMouseEventFilter.h is :
@
#include <QtCore/QEvent>
#include <QtCore/QObject>

class QMouseEventFilter : public QObject
{
Q_OBJECT
public:

QMouseEventFilter(QObject *parent = 0) : QObject(parent)
{
}

protected:

bool eventFilter(QObject * p_obj, QEvent * p_event)
{
if (p_event->type() == QEvent::MouseButtonDblClick ||
p_event->type() == QEvent::MouseButtonPress ||
p_event->type() == QEvent::MouseButtonRelease ||
p_event->type() == QEvent::Wheel)
{
p_event->ignore();
return true;
}
return false;
}
};
@

Enjoy

gladiatorchirag

Hi,
Thanks for your prompt reply, really helped me a lot.
I Updated your code a little bit and now both mouse and touch interaction are going on perfectly fine. Hope you and everyone else can also benefit from it.

@bool eventFilter(QObject * p_obj, QEvent * p_event)
{
if (p_event->type() == QEvent::MouseButtonDblClick ||
p_event->type() == QEvent::MouseButtonPress ||
p_event->type() == QEvent::MouseButtonRelease ||
p_event->type() == QEvent::Wheel)
{
QMouseEvent* pMouseEvent = dynamic_cast<QMouseEvent*>(p_event);
if ((pMouseEvent != NULL) && (pMouseEvent->source() == Qt::MouseEventSource::MouseEventSynthesizedBySystem))
{
p_event->ignore();
return true;
}
}
return false;
}@

Cheers!

ageblade

Hi again,
Can you please check this issue in Qt 5.4.1 ?
Maybe it got fixed in the new patch release

Thanks

ageblade

Hello fellow historians,

I checked this issue with Qt 5.5.1 and it is still seems to be an issue.
Did anyone got to fix this in more elegant manner ?

Bambi

Am suffering from the same issue.. still havent checked if it changed in 5.6