Connect the QGrapchisScene of QGraphicsView click signal

[aguayro]

I have a QGraphicsView and want to detect user clicks, but i have a problem, clickng the scrollbars also emit the click signal. How could i avoid the signal when scrollbars are clicked?

thsi is my code:

rs_Graphicsview::rs_Graphicsview(QWidget *parent) :
  QGraphicsView(parent)
{
 installEventFilter(this);
}
 
 
bool rs_Graphicsview::eventFilter(QObject *obj, QEvent *evnt) {
  if (evnt->type() == QEvent::MouseButtonPress) {
      emit clicked();
 
    }
     return QObject::eventFilter(obj, evnt);
}

rs_Graphicsview::rs_Graphicsview(QWidget *parent) :
  QGraphicsView(parent)
{
 installEventFilter(this);
}


bool rs_Graphicsview::eventFilter(QObject *obj, QEvent *evnt) {
  if (evnt->type() == QEvent::MouseButtonPress) {
      emit clicked();

    }
     return QObject::eventFilter(obj, evnt);
}

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[wysota]

Install the event filter on the view's viewport().

[Santosh Reddy]

What do want to achieve my getting user click on the QGraphicsView?

Install the event filter on the viewport

installEventFilter(this->viewport());

installEventFilter(this->viewport());

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Most of the cases it is more useful to receive (filter) on the QGraphicsScene?

Edit: I should improve my keyboard skills (it took ~10 min to type this )

[aguayro]

Using

installEventFilter(this->viewport());

installEventFilter(this->viewport());

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desn't work.

Just stops emitting clicked() signal.

[Santosh Reddy]

try this

bool rs_Graphicsview::eventFilter(QObject *obj, QEvent *evnt) {
  if (evnt->type() == QEvent::MouseButtonPress) {
      emit clicked();
 
    }
     //return QObject::eventFilter(obj, evnt);
    return false;
}

bool rs_Graphicsview::eventFilter(QObject *obj, QEvent *evnt) {
  if (evnt->type() == QEvent::MouseButtonPress) {
      emit clicked();

    }
     //return QObject::eventFilter(obj, evnt);
    return false;
}

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[aguayro]

It's strange, just does the opposite, works on scrollbar clicks, and ignores scene area clicks

[wysota]

That's because you didn't install the filter on the correct object.

It should be:

view->viewport()->installEventFilter(this);

view->viewport()->installEventFilter(this);

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[aguayro]

still emitting when scrolbar clicked, i must be clumsy, seems easy but something fails

[wysota]

Well... it works just fine for me...

#include <QtGui>
 
class Monitor : public QObject {
public:
  Monitor(QObject *parent = 0) : QObject(parent) {}
 
protected: 
  bool eventFilter(QObject *o, QEvent *e) {
    if(e->type() == QEvent::MouseButtonPress) {
      qDebug() << "CLICK";
    }
    return false;
  }
};
 
int main(int argc, char **argv) {
  QApplication app(argc, argv);
  QGraphicsView view;
  QGraphicsScene scene(0,0,2000,2000);
  view.setScene(&scene);
  Monitor monitor;
  view.viewport()->installEventFilter(&monitor);
  view.show();
  return app.exec();
}

#include <QtGui>

class Monitor : public QObject {
public:
  Monitor(QObject *parent = 0) : QObject(parent) {}
  
protected: 
  bool eventFilter(QObject *o, QEvent *e) {
    if(e->type() == QEvent::MouseButtonPress) {
      qDebug() << "CLICK";
    }
    return false;
  }
};

int main(int argc, char **argv) {
  QApplication app(argc, argv);
  QGraphicsView view;
  QGraphicsScene scene(0,0,2000,2000);
  view.setScene(&scene);
  Monitor monitor;
  view.viewport()->installEventFilter(&monitor);
  view.show();
  return app.exec();
}

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[Santosh Reddy]

Yes there is mistake in my post