c++qtsliderqevent

How to emit a signal if double clicking on slider handle


We are using Qt 5.10/C++ and I'm asked to implement a feature using the QSlider class.

My colleague wants me to emit a signal, whenever the user performs a double mouse click on the slider handle.

How can this be achieved. Maybe I have to reimplement

bool event(QEvent *e)

, but I don't know how to start.


Solution

  • Working solution

    With the help of the comments I derived a working solution:

    #pragma once
    
    #include <QSlider>
    #include <QMouseEvent>
    #include <QStyleOption>
    #include <QDebug>
    
    class DoubleClickSlider : public QSlider {
        Q_OBJECT
    public:
        DoubleClickSlider(QWidget* parent = nullptr) : QSlider(parent) { };
    
    signals:
        void sliderHandleDoubleClicked();
    
    protected:
        void mouseDoubleClickEvent(QMouseEvent *event) override {
            QStyleOptionSlider opt;
            this->initStyleOption(&opt);
            QRect sr = this->style()->subControlRect(QStyle::CC_Slider, &opt, QStyle::SC_SliderHandle, this);
    
            if (sr.contains(event->pos())) {
                qDebug() << "Double clicked handle";
                emit sliderHandleDoubleClicked();
            }
            QSlider::mouseDoubleClickEvent(event);
    
        }
    };