Global hotkeys and nativeEvent() is not working in Qt6

[wlivengood]

I've made a small application (as seen on several examples) that registers a global hotkey with WINAPI's RegisterHotKey() function and handles the event in QWidget's reimplemented nativeEvent().

The application behaves as I expect when compiled with Qt versions 5.12.3 and 5.15.2; however, when I compile with 6.2.4 or 6.5.0 the nativeEvent() function is never called.

Is there some additional settings that I need to utilize when using Qt6?

GlobalHotKeyTest.h

#pragma once

#include <QtWidgets/QMainWindow>
#include "ui_GlobalHotkeyTest.h"

#define HOTKEY_CTRL_ALT_S_ID    1

class GlobalHotkeyTest : public QMainWindow
{
    Q_OBJECT

public:
    GlobalHotkeyTest(QWidget *parent = nullptr);
    ~GlobalHotkeyTest();

protected:
    // The method for processing native events from the OS in Qt
    bool nativeEvent( const QByteArray& eventType, void* message, long* result );

private:
    Ui::GlobalHotkeyTestClass ui;
};

GlobalHotkeyTest.cpp

#include "GlobalHotkeyTest.h"
#include <windows.h>
#include <QMessageBox>

GlobalHotkeyTest::GlobalHotkeyTest(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

/*----------------------------------------------------------------
Windows Specific
Register Ctrl+Alt+S as a hotkey combo.
This registers the combo as a system-wide shortcut for this
application so you can stop jiggling even when the application
is not in the foreground.
----------------------------------------------------------------*/
    bool result = RegisterHotKey(
        (HWND)this->window()->winId(),
        HOTKEY_CTRL_ALT_S_ID,
        MOD_CONTROL | MOD_ALT,
        Qt::Key_S );

    if ( !result ) {
        DWORD error = GetLastError();
        LPSTR messageBuffer = nullptr;

        //Ask Win32 to give us the string version of that message ID.
        //The parameters we pass in, tell Win32 to create the buffer that holds the message for us (because we don't yet know how long the message string will be).
        size_t size = FormatMessageA( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                                      NULL, error, MAKELANGID( LANG_NEUTRAL, SUBLANG_DEFAULT ), (LPSTR)&messageBuffer, 0, NULL );

        //Copy the error message into a std::string.
        std::string message( messageBuffer, size );

        //Free the Win32's string's buffer.
        LocalFree( messageBuffer );

        QMessageBox::critical( this, "Failed to register hot key", QString::fromStdString( message ) );
    };
}

GlobalHotkeyTest::~GlobalHotkeyTest()
{
    UnregisterHotKey( (HWND)this->window()->winId(), HOTKEY_CTRL_ALT_S_ID );
}

bool GlobalHotkeyTest::nativeEvent( const QByteArray & eventType, void* message, long* result )
{
/*----------------------------------------------------------------
 Windows Specific
 Intercept the hotkey message from the windows event filter.
 //
 ----------------------------------------------------------------*/
    MSG* msg = static_cast<MSG*>( message );
    if ( msg->message == WM_HOTKEY ) {
        LPARAM combo = Qt::Key_S << 16 | MOD_CONTROL | MOD_ALT;
        bool result = msg->lParam & combo;

        QMessageBox::information(this,"Hotkey detected","The hotkey was detected");
        return( true );

    }

    return( false );
}

[hskoglund]

Hi, the function declaration of nativeEvent() has changed slightly in Qt6 so it will work again if you change:

// Qt5 flavor
bool nativeEvent( const QByteArray& eventType, void* message, long* result );

to

// Qt6 flavor
bool nativeEvent(const QByteArray& eventType, void* message, qintptr* result);

P.S Actually why not add the override spec. so you're prepared for Qt7 (if that had been in there in Qt5 you would got a compiler error today :-)

// preparing for Qt7 or later
bool nativeEvent(const QByteArray& eventType, void* message, qintptr* result) override;

[wlivengood]

@hskoglund Thanks for the pointing that out. I guess I did not pay close enough attention to the new declaration.