问题
I'm trying to get a global hotkey working in Linux using Mono. I found the signatures of XGrabKey and XUngrabKey, but I can't seem to get them working. Whenever I try to invoke XGrabKey, the application crashes with a SIGSEGV.
This is what I have so far:
using System;
using Gtk;
using System.Runtime.InteropServices;
namespace GTKTest
{
class MainClass
{
const int GrabModeAsync = 1;
public static void Main(string[] args)
{
Application.Init();
MainWindow win = new MainWindow();
win.Show();
// Crashes here
XGrabKey(
win.Display.Handle,
(int)Gdk.Key.A,
(uint)KeyMasks.ShiftMask,
win.Handle,
true,
GrabModeAsync,
GrabModeAsync);
Application.Run();
XUngrabKey(
win.Display.Handle,
(int)Gdk.Key.A,
(uint)KeyMasks.ShiftMask,
win.Handle);
}
[DllImport("libX11")]
internal static extern int XGrabKey(
IntPtr display,
int keycode,
uint modifiers,
IntPtr grab_window,
bool owner_events,
int pointer_mode,
int keyboard_mode);
[DllImport("libX11")]
internal static extern int XUngrabKey(
IntPtr display,
int keycode,
uint modifiers,
IntPtr grab_window);
}
public enum KeyMasks
{
ShiftMask = (1 << 0),
LockMask = (1 << 1),
ControlMask = (1 << 2),
Mod1Mask = (1 << 3),
Mod2Mask = (1 << 4),
Mod3Mask = (1 << 5),
Mod4Mask = (1 << 6),
Mod5Mask = (1 << 7)
}
}
Does anyone have a working example of XGrabKey?
Thanks!
回答1:
Well, I finally found a working solution in managed code. The SIGSEGV was happening because I was confusing the handles of the unmanaged Gdk objects with the handles of their X11 counterparts. Thanks to Paul's answer, I was able to find an unmanaged example of global hotkeys and familiarized myself with how it worked. Then I wrote my own unmanaged test program to find out what I needed to do without having to deal with any managed idiosyncrasies. After that was successful, I created a managed solution.
Here is the managed solution:
public class X11Hotkey
{
private const int KeyPress = 2;
private const int GrabModeAsync = 1;
private Gdk.Key key;
private Gdk.ModifierType modifiers;
private int keycode;
public X11Hotkey(Gdk.Key key, Gdk.ModifierType modifiers)
{
this.key = key;
this.modifiers = modifiers;
Gdk.Window rootWin = Gdk.Global.DefaultRootWindow;
IntPtr xDisplay = GetXDisplay(rootWin);
this.keycode = XKeysymToKeycode(xDisplay, (int)this.key);
rootWin.AddFilter(new Gdk.FilterFunc(FilterFunction));
}
public event EventHandler Pressed;
public void Register()
{
Gdk.Window rootWin = Gdk.Global.DefaultRootWindow;
IntPtr xDisplay = GetXDisplay(rootWin);
XGrabKey(
xDisplay,
this.keycode,
(uint)this.modifiers,
GetXWindow(rootWin),
false,
GrabModeAsync,
GrabModeAsync);
}
public void Unregister()
{
Gdk.Window rootWin = Gdk.Global.DefaultRootWindow;
IntPtr xDisplay = GetXDisplay(rootWin);
XUngrabKey(
xDisplay,
this.keycode,
(uint)this.modifiers,
GetXWindow(rootWin));
}
private Gdk.FilterReturn FilterFunction(IntPtr xEvent, Gdk.Event evnt)
{
XKeyEvent xKeyEvent = (XKeyEvent)Marshal.PtrToStructure(
xEvent,
typeof(XKeyEvent));
if (xKeyEvent.type == KeyPress)
{
if (xKeyEvent.keycode == this.keycode
&& xKeyEvent.state == (uint)this.modifiers)
{
this.OnPressed(EventArgs.Empty);
}
}
return Gdk.FilterReturn.Continue;
}
protected virtual void OnPressed(EventArgs e)
{
EventHandler handler = this.Pressed;
if (handler != null)
{
handler(this, e);
}
}
private static IntPtr GetXWindow(Gdk.Window window)
{
return gdk_x11_drawable_get_xid(window.Handle);
}
private static IntPtr GetXDisplay(Gdk.Window window)
{
return gdk_x11_drawable_get_xdisplay(
gdk_x11_window_get_drawable_impl(window.Handle));
}
[DllImport("libgtk-x11-2.0")]
private static extern IntPtr gdk_x11_drawable_get_xid(IntPtr gdkWindow);
[DllImport("libgtk-x11-2.0")]
private static extern IntPtr gdk_x11_drawable_get_xdisplay(IntPtr gdkDrawable);
[DllImport("libgtk-x11-2.0")]
private static extern IntPtr gdk_x11_window_get_drawable_impl(IntPtr gdkWindow);
[DllImport("libX11")]
private static extern int XKeysymToKeycode(IntPtr display, int key);
[DllImport("libX11")]
private static extern int XGrabKey(
IntPtr display,
int keycode,
uint modifiers,
IntPtr grab_window,
bool owner_events,
int pointer_mode,
int keyboard_mode);
[DllImport("libX11")]
private static extern int XUngrabKey(
IntPtr display,
int keycode,
uint modifiers,
IntPtr grab_window);
#if BUILD_FOR_32_BIT_X11
[StructLayout(LayoutKind.Sequential)]
internal struct XKeyEvent
{
public short type;
public uint serial;
public short send_event;
public IntPtr display;
public uint window;
public uint root;
public uint subwindow;
public uint time;
public int x, y;
public int x_root, y_root;
public uint state;
public uint keycode;
public short same_screen;
}
#elif BUILD_FOR_64_BIT_X11
[StructLayout(LayoutKind.Sequential)]
internal struct XKeyEvent
{
public int type;
public ulong serial;
public int send_event;
public IntPtr display;
public ulong window;
public ulong root;
public ulong subwindow;
public ulong time;
public int x, y;
public int x_root, y_root;
public uint state;
public uint keycode;
public int same_screen;
}
#endif
}
And here is the test program:
public static void Main (string[] args)
{
Application.Init();
X11Hotkey hotkey = new X11Hotkey(Gdk.Key.A, Gdk.ModifierType.ControlMask);
hotkey.Pressed += HotkeyPressed;;
hotkey.Register();
Application.Run();
hotkey.Unregister();
}
private static void HotkeyPressed(object sender, EventArgs e)
{
Console.WriteLine("Hotkey Pressed!");
}
I'm not sure how the XKeyEvent structure will behave on other systems with different sizes for C ints and longs, so whether this solution will work on all systems remains to be seen.
Edit: It looks like this solution is not going to be architecture-independent as I feared, due to the varying nature of the underlying C type sizes. libgtkhotkey looks promising as way to avoid deploying and compiling custom unmanaged libraries with your managed assemblies.
Note: Now you need to explicity define BUILD_FOR_32_BIT_X11 or BUILD_FOR_64_BIT_X11 depending on the word-size of your OS.
回答2:
I'm new to this site and it seems that I can't leave a comment on a previous question as I have insufficient reputation. (Sorry I can't even up-vote you!)
Relating to the issue of differing underlying sizes, I think this is solvable by using an IntPtr for the longs. This follows a suggestion in the Mono project documentation, see http://www.mono-project.com/Interop_with_Native_Libraries#Longs. The C types int and Bool should map to C# int.
Regarding the GAPI wrapper, I tried it, but couldn't get it working. If Zach could post any info on how he did it, I'd be grateful.
Also I couldn't get the sample program to work. Like SDX2000, I had to edit the library names, and I added using statements. I had a problem with Application.Init(), which in the end I swapped for creating a Form. But still my register call fails with BadRequest. If anyone who has got this working can update the code to make it more complete I'd be grateful.
回答3:
Tomboy has some code that knows how to do this, I'd take the code from there.
来源：https://stackoverflow.com/questions/2349958/global-hotkey-in-mono-and-gtk