detect if mouse buttons are pressed when sliding into widget

[sandro4912]

@Chris-Kawa said in detect if mouse buttons are pressed when sliding into widget:

if(event->type() == QEvent::MouseButtonPress)
{
QMouseEvent* mouse_event = static_cast<QMouseEvent*>(event);
// do something...
}

Ok I have one more concern. Before i handled mouseMoveEvent , mouseReleaseEvent and mousePressEvent in the Cell class. To implement them I used private functions and members of the Cell class. To implement the behaviour now i have to make them public or frind with the Event filter class. Doesn't that break encapusulation?

[Chris Kawa]

@sandro4912 said in detect if mouse buttons are pressed when sliding into widget:

To implement the behaviour now i have to make them public or frind with the Event filter class.

Can't you just call a public function on that Cell class that will call all those private things?

[sandro4912]

i tryed it out however i still have the same issue:

bool CellInputHandler::eventFilter(QObject *watched, QEvent *event)
{
    auto cell = qobject_cast<Cell *>(watched);

    if(event->type() == QEvent::MouseButtonPress){
       auto mouse_event = static_cast<QMouseEvent*>(event);
       cell->handleMousePressEvent(mouse_event);
       return true;
    }
    if(event->type() == QEvent::MouseButtonRelease){
       auto mouse_event = static_cast<QMouseEvent*>(event);
       cell->handleMouseReleaseEvent(mouse_event);
       return true;
    }
    if(event->type() == QEvent::MouseMove) {
        auto mouse_event = static_cast<QMouseEvent*>(event);
        QRect rect{cell->mapToGlobal(QPoint(0, 0)), cell->size()};

        if(rect.contains(mouse_event->globalPos())) {

            if(mouse_event->buttons() & Qt::LeftButton &&
                mouse_event->buttons() & Qt::RightButton) {

                cell->handleMouseMoveEventInside(mouse_event);
            }
        }
        else {
            cell->handleMouseMoveEventOutside(mouse_event);
        }
        return true;
    }
    return false;
}

Press and Release seem to work fine like they already did. However the move still only detects one widget.

In Cell i added this:

void Cell::handleMouseMoveEventInside(QMouseEvent *event)
{
        qDebug() << "Entered";
}

void Cell::handleMouseMoveEventOutside(QMouseEvent *event)
{
        qDebug() << "Left";
}

Still i only see Entered and Left from the widget i first clicked down the mouse buttons

[Asperamanca]

@sandro4912 It sounds a bit like a drag-and-drop operation to me. Wouldn't that work for you?

[sandro4912]

You mean using drag and drop in the event filter to transfer that mouse buttons are pressed both?

[mrjj]

@sandro4912
Hi
Do you have
setMouseTracking(true);
on widget 2 ?

[sandro4912]

@mrjj said in detect if mouse buttons are pressed when sliding into widget:

Hi

Yes it is enabled on both widgets(they are the same widgets)

[mrjj]

@sandro4912
Ok. :)
was just a shot.

[sandro4912]

I really wonder how the issue could get solved. Annother Information i maybe forgot to tell.

Both widgets are inside annother widget. Could that help?

[mrjj]

@sandro4912
Hi
The issue is that you only see

event->type() == QEvent::MouseMove

for one of the widgets ?

[ofmrew]

@mrjj I believe that you need to set a variable, addressable from each cell, that indicates that the mouse button has been pressed. My concern with this is that what happens if the mouse button is released in another widget? Hover events might be helpful.

[Chris Kawa]

The problem is you're checking the rectangle of the wrong widget. As I said the widget grabs mouse when you press, so cell is always gonna be the widget that gets the events, the one you pressed on, not the one you're hovering over.

You need to get the rectangle of the other widget from somewhere.

Here's a little working example. Maybe you'll find it useful:

#include <QApplication>
#include <QPushButton>
#include <QHBoxLayout>
#include <QEvent>
#include <QDebug>

struct FilterClass : public QObject
{
    bool eventFilter(QObject*, QEvent* evt)
    {
        if (evt->type() == QEvent::MouseMove)
        {
            auto move_evt = static_cast<QMouseEvent*>(evt);
            if (move_evt->buttons().testFlag(Qt::LeftButton) &&
                move_evt->buttons().testFlag(Qt::RightButton))
                qDebug() << "Mouse over" << qApp->widgetAt(move_evt->globalPos());
        }

        return false;
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    FilterClass filter;
    QWidget w;
    w.setLayout(new QHBoxLayout());
    w.layout()->addWidget(new QPushButton("Button 1"));
    w.layout()->addWidget(new QPushButton("Button 2"));
    for (auto c : w.children()) c->installEventFilter(&filter);

    w.show();
    return a.exec();
}

[sandro4912]

I could solve the issue with the example code.

I had to add a member which remembers the last cell in the event filer. Than i could solve my Issue like this:

if(event->type() == QEvent::MouseMove) {
    auto mouse_event = static_cast<QMouseEvent*>(event);
    QRect rect{cell->mapToGlobal(QPoint(0, 0)), cell->size()};

    if(mouse_event->buttons().testFlag(Qt::LeftButton) &&
        mouse_event->buttons().testFlag(Qt::RightButton)) {

        auto widget = qApp->widgetAt(mouse_event->globalPos());

        if(widget) {
            auto currentCell = qobject_cast<Cell *>(widget);

            if(!currentCell) {
                if(mLastCell) {
                    mLastCell->handleMouseMoveEventOutside(mouse_event);
                }
                mLastCell = nullptr;
                return true;
            }

            if(currentCell != mLastCell) {
                if(mLastCell) {
                    mLastCell->handleMouseMoveEventOutside(mouse_event);
                }
                currentCell->handleMouseMoveEventInside(mouse_event);
                mLastCell = currentCell;
            }
        }
        return true;
    }
}