Ignore and propagate QWidget click events to the OS

Question

I have a top-level parentless QWidget on top of which I have a bunch of other QWidgets(e.g. QPushButtons). I would like to make my QWidget act like it is transparent for mouse events. So when I click on the QWidget(but not on my buttons) I want my window to lose focus and something in the back to be selected(e.g. a Windows Explorer window if it happens to be in the back of my window). I also want my QPushButtons to continue processing mouse events.

Is this possible? I tried setting the Qt::WA_TranslucentBackground and Qt::WA_TransparentForMouseEvents on the widget but if I draw something on it, e.g. a QGraphicsDropShadowEffect the widget still processes mouse click events on the parts where QGraphicsDropShadowEffect draws on it.

Is this possible?

Regards!

What version of Qt is this, and what platform? Last time I checked, `WA_TransparentForMouseEvents` only acted within the widget hierarchy and would not pass any mouse events "back" to the operating system. — Kuba hasn't forgotten Monica, Sep 12 '14 at 19:02

Jablonski · Accepted Answer · 2014-09-12T19:14:18.387

I found some solution. In my case this - is the pointer to QMainWindow. Main idea: catch click, get globalPos, hide window and give click to OS. But it should be OS specific code, I can give you example which works on Windows. You should create eventFilter (I hope you know how to do this, so I post next code).

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
    if(obj == this && event->type() == QEvent::MouseButtonRelease)
    {
        qDebug() << "mouse";
        QMouseEvent *mouse = static_cast<QMouseEvent*>(event);
        qDebug() << mouse->globalPos();
        QPoint point = mouse->globalPos();
        this->hide();
        //start of OS specific code
        mouse_event(MOUSEEVENTF_LEFTDOWN,point.x(),point.y(),0,0);
        mouse_event(MOUSEEVENTF_LEFTUP,point.x(),point.y(),0,0);
        mouse_event(MOUSEEVENTF_LEFTDOWN,point.x(),point.y(),0,0);
        mouse_event(MOUSEEVENTF_LEFTUP,point.x(),point.y(),0,0);
        //this->show();//as you want
    }

return QObject::eventFilter(obj, event);
}

In my example, window will hide and we emulate doubleclick. On my computer I can ignore QMainWindow and open picture which was closed by QMainWindow(I couldn't saw it, I saw only my QMainWindow, but click was ignored and we gave this click to OS)

Ignore and propagate QWidget click events to the OS

1 Answers1