CODEWITHSUNDEEP
c++qt
Yuri Yaryshev
Yuri Yaryshev

Reputation: 1041

Qt event when widget goes out of sight

Is there a way in Qt to handle situation when any widget of Window goes out of sight. I.e if a widget was in tab control and user have changed active tab, or if user just scrolls and widget goes offscreen, and also when it goes back on screen.

Is that possible to add some code to this two events?

Best if this can be done globally...

Upvotes: 2

Views: 1901

Answers (1)

Alexander V
Alexander V

Reputation: 8698

Is there a way in Qt to handle situation when any widget of Window goes out of sight. I.e if a widget was in tab control and user have changed active tab, or if user just scrolls and widget goes offscreen, and also when it goes back on screen.

The way the question asked makes one think that the widget show-hide-expose state changes need to be handled:

bool MyWidget::event(QEvent* pEvent)
{
    if (pEvent->type() == QEvent::Show)
    {
      // event "shown"
    }
    else if (pEvent->type() == QEvent::Hide)
    {
      // event "hidden"
    }
    else if (pEvent->type() == QEvent::Expose)
    {
      // event "exposure changed"
      // deal with QExposeEvent and evaluate the exposed region
      // QExposeEvent* pExposeEvent = reinterpret_cast<QExposeEvent*>(pEvent);
    }
    return QWidget::event(pEvent);
}

Best if this can be done globally...

Event filter at the top level widget may solve that. Or you can override event() function for the top level widget but finding what exact widget was affected is another thing.

Refer to QExposeEvent description.

Upvotes: 1

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