Is it possible to use Win32 Hooks in Qt applications - c++

Question

I like to know if its possible to use win32 keyboard hook function (SetWindowsHookEx , SetWindowsHookEx ) in a Qt application.
If possible pls provide a sample code on using SetWindowsHookEx , SetWindowsHookEx functions in Qt.
//Update as of 18 Feb 2010 //
I havent figured out how to do that in QT yet.
But as a workaround I have created a win32 dll using vc++ express edition and placed my hook commands inside the dll functions.
And I call that dll functions from Qt using QLibrary class
/* hearder file code*/
QLibrary *myLib;
typedef HHOOK (*MyPrototype)(HINSTANCE);
/* source file code */
myLib = new QLibrary( "ekhook.dll" );
MyPrototype myFunction;
myFunction = (MyPrototype) myLib->resolve( "Init" );
init() is the function in ekhook.dll thats being called

Answer 1

I was wondering the same thing and found this finally.. Credit goes to Voidrealms.
The video explains enough to make a working application with the following code below.
//Copied Code from YouTube Video
#include <QtCore/QCoreApplication>
#include <QDebug>
#include <QTime>
#include <QChar>
#include <iostream>
#include <windows.h>
#pragma comment(lib, "user32.lib")
HHOOK hHook = NULL;
using namespace std;
void UpdateKeyState(BYTE *keystate, int keycode)
{
keystate[keycode] = GetKeyState(keycode);
}
LRESULT CALLBACK MyLowLevelKeyBoardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
//WPARAM is WM_KEYDOWn, WM_KEYUP, WM_SYSKEYDOWN, or WM_SYSKEYUP
//LPARAM is the key information
qDebug() << "Key Pressed!";
if (wParam == WM_KEYDOWN)
{
//Get the key information
KBDLLHOOKSTRUCT cKey = *((KBDLLHOOKSTRUCT*)lParam);
wchar_t buffer[5];
//get the keyboard state
BYTE keyboard_state[256];
GetKeyboardState(keyboard_state);
UpdateKeyState(keyboard_state, VK_SHIFT);
UpdateKeyState(keyboard_state, VK_CAPITAL);
UpdateKeyState(keyboard_state, VK_CONTROL);
UpdateKeyState(keyboard_state, VK_MENU);
//Get keyboard layout
HKL keyboard_layout = GetKeyboardLayout(0);
//Get the name
char lpszName[0X100] = {0};
DWORD dwMsg = 1;
dwMsg += cKey.scanCode << 16;
dwMsg += cKey.flags << 24;
int i = GetKeyNameText(dwMsg, (LPTSTR)lpszName, 255);
//Try to convert the key information
int result = ToUnicodeEx(cKey.vkCode, cKey.scanCode, keyboard_state, buffer, 4, 0, keyboard_layout);
buffer[4] = L'\0';
//Print the output
qDebug() << "Key: " << cKey.vkCode << " " << QString::fromUtf16((ushort*)buffer) << " " << QString::fromUtf16((ushort*)lpszName);
}
return CallNextHookEx(hHook, nCode, wParam, lParam);
}
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
hHook = SetWindowsHookEx(WH_KEYBOARD_LL, MyLowLevelKeyBoardProc, NULL, 0);
if (hHook == NULL)
{
qDebug() << "Hook Failed" << endl;
}
return a.exec();
}

Answer 2

You don't need to do anything with Qt. Just follow the windows examples:
http://msdn.microsoft.com/en-us/library/ms644960(VS.85).aspx

Answer 3

I believe it is possible, yes. Use QWidget::winId.