在Java swing中创建X window（X11）并获取其ID

Question

有人可以帮助我使用Eclipse在Java swing中创建X11窗口吗？还有获取X11 ID的函数。在Java中创建X11窗口的基本要求是什么。

Answer 1

Tom answered the first part of your question. The second part of the answer is: to get the id of an X11 window you are going to have to use native code (code written in C or C++) and access it through the JNI interface.

You may have to run a search by title through all existing windows to get the one you desire.

Here is a recursive function that will search (starting from the root window) for a window with the desired name

Window windowWithName(Display *dpy, Window top, char *name)
{
    Window *children, dummy;
    unsigned int nchildren;
    unsigned int i;
    Window w = 0;
    char *window_name;

    if (XFetchName(dpy, top, &window_name) && !strcmp(window_name, name))
        return (top);

    if (!XQueryTree(dpy, top, &dummy, &dummy, &children, &nchildren))
        return (0);

    for (i = 0; i < nchildren; i++)
    {
        w = windowWithName(dpy, children[i], name);
        if (w)
            break;
    }
    if (children)
        XFree((char *) children);
    return (w);
}

Note: **unfortunately there is a well documented memory leak in the XFetchName function implemented in X11 that was never fixed. If you run valgrind and have minor memory leak issues this is whats causing them.

Answer 2

Just to expand the answers @Zubzub and @ArtemGr gave, the following minimalistic AWT example works for me, at least in Sun 's Java 1.8:

import java.awt.Dimension;

import javax.swing.JFrame;

import sun.awt.X11.XWindow;

class C {
    public static void main(final String args[]) {
        final JFrame frame = new JFrame();
        frame.setPreferredSize(new Dimension(200, 200));
        frame.pack();
        frame.setVisible(true);
        final XWindow xWindow = (XWindow) frame.getPeer();
        frame.setTitle("Window id: 0x" + Long.toHexString(xWindow.getWindow()));
    }
}

Once the window is visible, you can verify its id with xwininfo utility.

Please note, however, that even provided your AWT application will only run under X11 , the above solution is not portable:

• GCJ will use gnu.java.awt.peer.gtk.GtkFramePeer , and
• older Sun JDK versions (1.4 and below) will use sun.awt.motif.MFramePeer . Despite XToolkit is the default on Sun JDK starting with 1.5, old MToolkit can still be re-enabled on 1.5 and 1.6, and
• I'm not sure about IBM J9 , BEA JRockit , Oracle lwAWT and Apache Harmony .

Answer 3

Creating an X11 window in Swing is as easy as new Frame() followed by setVisible(true) . Getting any of the unabstracted details will be harder. Of course, you can always open a java.net.Socket to port 6000 or so and speak X11 yourself.

Answer 4

If you're using a Sun JVM and don't mind overriding package access using reflection and "setAccessible(true)", then you can create an X11 window using the Sun's toolkit. https://www.docjar.com/docs/api/sun/awt/X11/XWindow.html

Not all methods of the toolkit might be present, though: I suspect methods not used in the toolkit itself were removed. For example, most of the XlibUtil aren't there. Here's an example how to use reflection to access the toolkit methods, in Scala: http://gist.github.com/567076

You can also use JNA to code xlib parts in Java; see question: Using Xlib via JNA to move a window

Answer 5

For those out there still looking for this:

You need to find the most toplevel component of your program and get the component's 'componentpeer'. Under linux this will be of type XComponent peer which extends XWindow which extends XBaseWindow. XBaseWindow has an attribute window of type long. That's what you're looking for. You probably need to use reflection to get to it.

hf