Qt: Defining a custom event type

Question

I have created a custom event in my Qt application by subclassing QEvent.

class MyEvent : public QEvent
{
  public:
    MyEvent() : QEvent((QEvent::Type)20         


        

Answer 1

For convenience, you can use the QEvent::registerEventType() static function to register and reserve a custom event type for your application. Doing so will allow you to avoid accidentally re-using a custom event type already in use elsewhere in your application.

Example:

class QCustomEvent : public QEvent
{
public:
    QCustomEvent() : QEvent(QCustomEvent::type())
    {}

    virtual ~QCustomEvent()
    {}

    static QEvent::Type type()
    {
        if (customEventType == QEvent::None)
        {
            int generatedType = QEvent::registerEventType()
            customEventType = static_cast(generatedType);
        }
        return customEventType;
    }

private:
    static QEvent::Type customEventType;
};

QEvent::Type QCustomEvent::customEventType = QEvent::None;