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Re: How to set a global (system) keyboard hook? [message #23146 is a reply to message #23135]

Fri, 18 September 2009 16:03

tojocky
Messages: 607
Registered: April 2008
Location: UK

Contributor

About global hotkey!

FOR WIN32:

acourding by simple example from

http://msdn.microsoft.com/en-us/library/ms646309(VS.85).aspx?ppud=4

first we need to register hot key by calling:

BOOL RegisterHotKey(      
    HWND hWnd,
    int id,
    UINT fsModifiers,
    UINT vk
);

and in U++ is already created a thread that execute function DWORD WINAPI Ctrl::Win32OverwatchThread(LPVOID). In this function is:

DWORD WINAPI Ctrl::Win32OverwatchThread(LPVOID)
{
    ............
	MSG Msg;
=>>HERE	while(GetMessage(&Msg, NULL, 0, 0) > 0) {
        TranslateMessage(&Msg);
==>>HERE we can process our keyboard event
	if(IsWindowUnicode(Msg.hwnd))
		DispatchMessageW(&Msg); // send to aprpopiate phread
	else
		DispatchMessage(&Msg);
    }
   .....................
}

The problem is that I do not get keycode property from Msg. From where can I get it?

for linux X11:

acording by documentation from:
1. http://www.xfree.org/current/XGrabKey.3.html#toc2

The simple code like this:

Window root;
XEvent ev;
    
Display * dpy = XOpenDisplay(0);

if(!dpy) return 1;

root = DefaultRootWindow(dpy);


char * key_string = "F3";

KeyCode key = XKeysymToKeycode(dpy, XStringToKeysym(key_string));

XGrabKey(dpy, key , AnyModifier, root,
    True, GrabModeAsync, GrabModeAsync);

for(;;)
{
	XNextEvent(dpy, &ev);
	if(ev.type == KeyPress && ev.xkey.keycode == key){
==>> Do our action
	}
}

First we need register global hotkey by calling:

nt XGrabKey(Display *display, int keycode, unsigned int
modifiers, Window grab_window, Bool owner_events, int pointer_mode, int keyboard_mode);

In u++ we can get message from void Ctrl::EventLoop0(Ctrl *ctrl)

which call void Ctrl::ProcessEvent(XEvent *event)

The good news is that I have keycode from the returned message. like this "ev.xkey.keycode".

The Question:

2. Is possible to add in u++ cros-os method for register global hotkey event?

For first I propouse like this:

static bool Ctrl::AddGlobalHotkey(Key p_key, callback 
p_func)

2. If is possible for register global hotkey event, maybe it is possible to unregister global hotkey event.

Maybe I was not understandable.

UPDATE:

Fro linux I found interesting example:

void
xstuff_grab_key_on_all_screens (int      keycode,
				guint    modifiers,
				gboolean grab)
	
{
	GdkDisplay *display;
	int         n_screens;
	int         i;

	display   = gdk_display_get_default ();
	n_screens = gdk_display_get_n_screens (display);

	for (i = 0; i < n_screens; i++) {
		GdkWindow *root;

		root = gdk_screen_get_root_window (
				gdk_display_get_screen (display, i));

		if (grab)
			XGrabKey (gdk_x11_display_get_xdisplay (display),
				  keycode, modifiers,
				  gdk_x11_drawable_get_xid (root),
				  True, GrabModeAsync, GrabModeAsync);
		else
			XUngrabKey (gdk_x11_display_get_xdisplay (display),
				    keycode, modifiers,
				    gdk_x11_drawable_get_xid (root));
	}
}

UPDATE 2:

Good news is for win32 too. It returns keycode in Mgs->lParam.

Ion Lupascu (tojocky).

[Updated on: Fri, 18 September 2009 17:05]

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