Get HWND on windows with Qt5 (from WId)

Question

I am trying to convert a Qt4 Application to Qt5. The only thing I couldn't figure out is how to get the HWND of a Widget. The program uses EcWin7 to show the progress on the taskbar icon on win 7+ but expects a HWND. The lib itself seems to compile fine after changing Q_WS_WIN to Q_OS_WIN) In Qt4 on Windows WId was just a typedef for HWND, so this was no problem. In Qt5 this is not the case anymore. I found some mailing list posting that could give a clue but it seems QPlatformNativeInterface is not part of the public API of Qt5 anymore.

The program calls EcWin7.init(this->winId()); and I need to some way to convert this ID into the HWND id or some other way to get this.

Well, that's strange. [QWidget::winId()](http://qt-project.org/doc/qt-5.0/qtwidgets/qwidget.html#winId) should return HWND on Windows, as it was in Qt4. — Maciej, Dec 27 '12 at 09:22

score 26 · Accepted Answer · edited Jan 30 '14 at 22:37

26

In Qt5 winEvent was replaced by nativeEvent:

bool winEvent(MSG* pMsg, long* result)

is now

bool nativeEvent(const QByteArray & eventType, void * message, long *result)

And in EcWin7::winEvent you have to cast void to MSG:

bool EcWin7::winEvent(void * message, long * result)
{
    MSG* msg = reinterpret_cast<MSG*>(message);
    if (msg->message == mTaskbarMessageId)
    {
      ...

I was able to get the application to work! Just replace:

 mWindowId = wid;

with

 mWindowId = (HWND)wid;

edited Jan 30 '14 at 22:37

Strigoides

4,329
5
23
25

answered Apr 21 '13 at 23:59

MrElmar

288
3
6

Unfortunatly, there are a lot of bugs. Not all events are passed to real widget, a lot of them are passed to top-level widget. – Dmitry Sazonov Mar 19 '15 at 13:25

score 11 · Answer 2 · answered Jan 24 '13 at 11:27

#include <QtGui/5.0.0/QtGui/qpa/qplatformnativeinterface.h>

static QWindow* windowForWidget(const QWidget* widget) 
{
    QWindow* window = widget->windowHandle();
    if (window)
        return window;
    const QWidget* nativeParent = widget->nativeParentWidget();
    if (nativeParent) 
        return nativeParent->windowHandle();
    return 0; 
}

HWND getHWNDForWidget(const QWidget* widget)
{
    QWindow* window = ::windowForWidget(widget);
    if (window && window->handle())
    {
        QPlatformNativeInterface* interface = QGuiApplication::platformNativeInterface();
        return static_cast<HWND>(interface->nativeResourceForWindow(QByteArrayLiteral("handle"), window));
    }
    return 0; 
}

corroboration, and further details how to get this to compile: http://lists.qt-project.org/pipermail/interest/2013-June/007650.html — David Burson, Feb 21 '14 at 18:06

score 3 · Answer 3 · edited Jan 09 '13 at 22:41

3

You may try:

(HWND)QWidget::winId();

edited Jan 09 '13 at 22:41

kmatyaszek

19,016
9
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answered Jan 09 '13 at 22:23

TheFox

39
1

score 2 · Answer 4 · answered Dec 27 '12 at 09:33

2

Try this function: QWindowsNativeInterface::nativeResourceForWindow

answered Dec 27 '12 at 09:33

score 2 · Answer 5 · answered Jul 13 '13 at 05:12

winId() worked for me on Qt 5.1 at least it has the same value when I'm using

bool Widget::nativeEvent(const QByteArray & eventType, void * message, long * result)
{
    MSG* msg = reinterpret_cast<MSG*>(message);
    qDebug() << msg->hwnd;

    return false;
}

and

qDebug() << winId();

Get HWND on windows with Qt5 (from WId)

5 Answers5

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