Right mouse functionality in QPushButton

Question

I want to achieve all the functionality of left button of mouse ( such as clicked(), pressed() , released() , setAutoRepeat() ) on QPushButton from the right button of mouse keeping all the left button functionality intact. Here is the code for re implementation of the eventFilter , which is not giving desirable result.

bool PreciseControl::eventFilter(QObject *, QEvent *event) 
{
QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);


if(event->type() == QEvent::MouseButtonPress &&
                    mouseEvent->button()==Qt::RightButton )
 {


        emit rightMousePressed();
        return true;
 }
else if(event->type() == QEvent::MouseButtonRelease &&
        mouseEvent->button()==Qt::RightButton )
{
        emit rightMouseReleased();
        return true;
}


if(event->type() == QEvent::MouseButtonPress &&
                    mouseEvent->button()==Qt::LeftButton )
 {


        emit leftMousePressed();
        return true;
 }
else if(event->type() == QEvent::MouseButtonRelease &&
        mouseEvent->button()==Qt::LeftButton )
{
        emit leftMouseReleased();
        return true;
}

 return false;}

Can any one help? Thanks in advance.

Answer 1

You shouldn't use event filters for this. Subclass QPushButton and implement your own right click handling. Here is a working example (I didn't test it thoroughly, so there might be some problems):

#include <QApplication>
#include <QPushButton>
#include <QMouseEvent>
#include <QLayout>
#include <QDebug>

class CustomButton : public QPushButton
{
    Q_OBJECT
public:
    explicit CustomButton(QWidget *parent = 0) : QPushButton(parent){}

protected:
    void mousePressEvent(QMouseEvent *e)
    {
        if(e->button() == Qt::RightButton && hitButton(e->pos()))
        {
            setDown(true);
            emit pressed();
        }
        QPushButton::mousePressEvent(e);
    }

    void mouseMoveEvent(QMouseEvent *e)
    {
        if(e->buttons() & Qt::RightButton)
        {
            if(hitButton(e->pos()) != isDown())
                setDown(!isDown());
        }
        QPushButton::mouseMoveEvent(e);
    }

    void mouseReleaseEvent(QMouseEvent *e)
    {
        if(e->button() == Qt::RightButton)
        {
            setDown(false);
            if(hitButton(e->pos()))
                click();
        }
        QPushButton::mouseReleaseEvent(e);
    }
};

void buttonClicked()
{
    qDebug() << "CLICKED";
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QWidget w;
    w.resize(500,500);
    w.setLayout(new QVBoxLayout);
    CustomButton button;
    button.setAutoRepeat(true);
    QObject::connect(&button, &CustomButton::clicked, &buttonClicked);
    w.layout()->addWidget(&button);
    w.show();

    return a.exec();
}

#include "main.moc"

If you want to differentiate between the right click and the left click, then see the source code for QAbstractButton::click, and implement your own for the right click.

Answer 2

You can implement the functionality in an event filter, and install it on the button(s) you want to be right-clickable.

// https://github.com/KubaO/stackoverflown/tree/master/questions/right-to-left-event-39220180
#include <QtWidgets>

class RightToLeftClick : public QObject {
    bool eventFilter(QObject *watched, QEvent *event) {
        if (event->type() == QEvent::MouseButtonDblClick ||
                event->type() == QEvent::MouseButtonPress ||
                event->type() == QEvent::MouseButtonRelease) {
            auto ev = static_cast<QMouseEvent*>(event);
            if (ev->button() == Qt::RightButton) {
                auto buttons = ev->buttons();
                if (buttons & Qt::RightButton) {
                    buttons ^= Qt::RightButton;
                    buttons |= Qt::LeftButton;
                }
                QMouseEvent lev{ev->type(),
                            ev->localPos(),
                            ev->windowPos(),
                            ev->screenPos(),
                            Qt::LeftButton,
                            buttons,
                            ev->modifiers(),
                            ev->source()};
                Q_ASSERT(! (lev.buttons() & Qt::RightButton));
                QCoreApplication::sendEvent(watched, &lev);
                return true;
            }
        }
        return QObject::eventFilter(watched, event);
    }
public:
    explicit RightToLeftClick(QObject * parent = nullptr) : QObject{parent} {
        addTo(parent);
    }
    void addTo(QObject * obj) {
        if (obj) obj->installEventFilter(this);
    }
};

Here's how to use it:

int main(int argc, char ** argv) {
    QApplication app{argc, argv};
    QWidget ui;
    QVBoxLayout layout{&ui};
    QPushButton button1{"Left Click Me"};
    QPushButton button2{"Right Click Me"};
    layout.addWidget(&button1);
    layout.addWidget(&button2);
    ui.show();
    RightToLeftClick rtl{&button2};
    return app.exec();
}