我的目标是拥有一个程序,该程序在后台休眠,但可由用户通过某些“热键”激活。通过深入研究Xlib手册和Xlib O'reilly手册,我了解到正确的方法是使用XGrabKey。但是,我对过程的理解是不正确的,因为简单的概念证明不起作用。
我的理解是,如果我用根窗口作为grab_window调用XGrabKey,并且owner_events为false,那么每当按下我的热键时,事件只会发送到根窗口。如果然后从根窗口中选择KeyPress事件,然后侦听X事件,则在按下热键时应该会收到一个按键事件。我在下面粘贴了一个最小的示例。
我希望在运行程序时,无论哪个窗口具有焦点,如果按下Ctrl + Shift + K,我的程序都应该输出“按下热键!”在控制台中,然后终止。
此外,据我了解,如果XGrabKey失败,则默认错误处理程序将显示一条消息,由于并非如此,因此我假设调用成功。
显然,我的理解存在某种缺陷。谁能指出我正确的方向?
#include <iostream>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
using namespace std;
int main()
{
Display* dpy = XOpenDisplay(0);
Window root = DefaultRootWindow(dpy);
XEvent ev;
unsigned int modifiers = ControlMask | ShiftMask;
int keycode = XKeysymToKeycode(dpy,XK_Y);
Window grab_window = root;
Bool owner_events = False;
int pointer_mode = GrabModeAsync;
int keyboard_mode = GrabModeAsync;
XGrabKey(dpy, keycode, modifiers, grab_window, owner_events, pointer_mode,
keyboard_mode);
XSelectInput(dpy, root, KeyPressMask );
while(true)
{
bool shouldQuit = false;
XNextEvent(dpy, &ev);
switch(ev.type)
{
case KeyPress:
cout << "Hot key pressed!" << endl;
XUngrabKey(dpy,keycode,modifiers,grab_window);
shouldQuit = true;
default:
break;
}
if(shouldQuit)
break;
}
XCloseDisplay(dpy);
return 0;
}
最佳答案
您的程序在这里工作。我的猜测是您还有另一个修改器处于 Activity 状态,例如NumLock。 GrabKey仅适用于精确的修饰符蒙版。
例如,这是来自metacity窗口管理器的一些(GPL)代码
/* Grab/ungrab, ignoring all annoying modifiers like NumLock etc. */
static void
meta_change_keygrab (MetaDisplay *display,
Window xwindow,
gboolean grab,
int keysym,
unsigned int keycode,
int modmask)
{
unsigned int ignored_mask;
/* Grab keycode/modmask, together with
* all combinations of ignored modifiers.
* X provides no better way to do this.
*/
meta_topic (META_DEBUG_KEYBINDINGS,
"%s keybinding %s keycode %d mask 0x%x on 0x%lx\n",
grab ? "Grabbing" : "Ungrabbing",
keysym_name (keysym), keycode,
modmask, xwindow);
/* efficiency, avoid so many XSync() */
meta_error_trap_push (display);
ignored_mask = 0;
while (ignored_mask <= display->ignored_modifier_mask)
{
if (ignored_mask & ~(display->ignored_modifier_mask))
{
/* Not a combination of ignored modifiers
* (it contains some non-ignored modifiers)
*/
++ignored_mask;
continue;
}
if (meta_is_debugging ())
meta_error_trap_push_with_return (display);
if (grab)
XGrabKey (display->xdisplay, keycode,
modmask | ignored_mask,
xwindow,
True,
GrabModeAsync, GrabModeSync);
else
XUngrabKey (display->xdisplay, keycode,
modmask | ignored_mask,
xwindow);
if (meta_is_debugging ())
{
int result;
result = meta_error_trap_pop_with_return (display, FALSE);
if (grab && result != Success)
{
if (result == BadAccess)
meta_warning (_("Some other program is already using the key %s with modifiers %x as a binding\n"), keysym_name (keysym), modmask | ignored_mask);
else
meta_topic (META_DEBUG_KEYBINDINGS,
"Failed to grab key %s with modifiers %x\n",
keysym_name (keysym), modmask | ignored_mask);
}
}
++ignored_mask;
}
meta_error_trap_pop (display, FALSE);
}
关于x11 - X11/Xlib的全局热键,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4037230/