Java – turns off the hook that captures global input events
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Java
introduce
This is an illustrative example Consider that I am tracking and displaying the global current position of the mouse and finally clicking the button and positioning it to the user This is a picture:
To archive and capture click events in the windows box, they will be sent to the event message queue of other programs. I use WinAPI, namely user32 DLL library to create a hook This is outside the JDK sandbox, so I use JNA to call the native library
All this was perfect, but it didn't close as I expected
My question is – how do I close the following sample programs correctly?
Sample source
The following code is not completely written by me, but is taken from this problem in Oracle forum and partially fixed
import java.awt.AWTException;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import com.sun.jna.Native;
import com.sun.jna.NativeLong;
import com.sun.jna.Platform;
import com.sun.jna.Structure;
import com.sun.jna.platform.win32.BaseTSD.ULONG_PTR;
import com.sun.jna.platform.win32.Kernel32;
import com.sun.jna.platform.win32.User32;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.LRESULT;
import com.sun.jna.platform.win32.WinDef.WPARAM;
import com.sun.jna.platform.win32.WinUser.HHOOK;
import com.sun.jna.platform.win32.WinUser.HOOKPROC;
import com.sun.jna.platform.win32.WinUser.MSG;
import com.sun.jna.platform.win32.WinUser.POINT;
public class MouseExample {
final JFrame jf;
final JLabel jl1,jl2;
final CWMouseHook mh;
final Ticker jt;
public class Ticker extends Thread {
public boolean update = true;
public void done() {
update = false;
}
public void run() {
try {
Point p,l = MouseInfo.getPointerInfo().getLocation();
int i = 0;
while (update == true) {
try {
p = MouseInfo.getPointerInfo().getLocation();
if (!p.equals(l)) {
l = p;
jl1.setText(new GlobalMouseClick(p.x,p.y)
.toString());
}
Thread.sleep(35);
} catch (InterruptedException e) {
e.printStackTrace();
return;
}
}
} catch (Exception e) {
update = false;
}
}
}
public MouseExample() throws AWTException,UnsupportedOperationException {
this.jl1 = new JLabel("{}");
this.jl2 = new JLabel("{}");
this.jf = new JFrame();
this.jt = new Ticker();
this.jt.start();
this.mh = new CWMouseHook() {
@Override
public void globalClickEvent(GlobalMouseClick m) {
jl2.setText(m.toString());
}
};
mh.setMouseHook();
jf.setLayout(new GridLayout(2,2));
jf.add(new JLabel("Position"));
jf.add(jl1);
jf.add(new JLabel("Last click"));
jf.add(jl2);
jf.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
mh.dispose();
jt.done();
jf.dispose();
}
});
jf.setLocation(new Point(0,0));
jf.setPreferredSize(new Dimension(200,90));
jf.pack();
jf.setVisible(true);
}
public static class GlobalMouseClick {
private char c;
private int x,y;
public GlobalMouseClick(char c,int x,int y) {
super();
this.c = c;
this.x = x;
this.y = y;
}
public GlobalMouseClick(int x,int y) {
super();
this.x = x;
this.y = y;
}
public char getC() {
return c;
}
public void setC(char c) {
this.c = c;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
@Override
public String toString() {
return (c != 0 ? c : "") + " [" + x + "," + y + "]";
}
}
public static class CWMouseHook {
public User32 USER32INST;
public CWMouseHook() throws UnsupportedOperationException {
if (!Platform.isWindows()) {
throw new UnsupportedOperationException(
"Not supported on this platform.");
}
USER32INST = User32.INSTANCE;
mouseHook = hookTheMouse();
Native.setProtected(true);
}
private static LowLevelMouseProc mouseHook;
private HHOOK hhk;
private boolean isHooked = false;
public static final int WM_LBUTTONDOWN = 513;
public static final int WM_LBUTTONUP = 514;
public static final int WM_RBUTTONDOWN = 516;
public static final int WM_RBUTTONUP = 517;
public static final int WM_MBUTTONDOWN = 519;
public static final int WM_MBUTTONUP = 520;
public void dispose() {
unsetMouseHook();
mousehook_thread = null;
mouseHook = null;
hhk = null;
USER32INST = null;
}
public void unsetMouseHook() {
isHooked = false;
USER32INST.UnhookWindowsHookEx(hhk);
System.out.println("Mouse hook is unset.");
}
public boolean isIsHooked() {
return isHooked;
}
public void globalClickEvent(GlobalMouseClick m) {
System.out.println(m);
}
private Thread mousehook_thread;
public void setMouseHook() {
mousehook_thread = new Thread(new Runnable() {
@Override
public void run() {
try {
if (!isHooked) {
hhk = USER32INST.SetWindowsHookEx(14,mouseHook,Kernel32.INSTANCE.GetModuleHandle(null),0);
isHooked = true;
System.out
.println("Mouse hook is set. Click anywhere.");
// message dispatch loop (message pump)
MSG msg = new MSG();
while ((USER32INST.GetMessage(msg,null,0)) != 0) {
USER32INST.TranslateMessage(msg);
USER32INST.DispatchMessage(msg);
if (!isHooked)
break;
}
} else
System.out
.println("The Hook is already installed.");
} catch (Exception e) {
System.err.println("Caught exception in MouseHook!");
}
}
});
mousehook_thread.start();
}
private interface LowLevelMouseProc extends HOOKPROC {
LRESULT callback(int nCode,WPARAM wParam,MOUSEHOOKSTRUCT lParam);
}
private LowLevelMouseProc hookTheMouse() {
return new LowLevelMouseProc() {
@Override
public LRESULT callback(int nCode,MOUSEHOOKSTRUCT info) {
if (nCode >= 0) {
switch (wParam.intValue()) {
case CWMouseHook.WM_LBUTTONDOWN:
globalClickEvent(new GlobalMouseClick('L',info.pt.x,info.pt.y));
break;
case CWMouseHook.WM_RBUTTONDOWN:
globalClickEvent(new GlobalMouseClick('R',info.pt.y));
break;
case CWMouseHook.WM_MBUTTONDOWN:
globalClickEvent(new GlobalMouseClick('M',info.pt.y));
break;
default:
break;
}
}
return USER32INST.CallNextHookEx(hhk,nCode,wParam,info.getPointer());
}
};
}
public class Point extends Structure {
public class ByReference extends Point implements
Structure.ByReference {
};
public NativeLong x;
public NativeLong y;
}
public static class MOUSEHOOKSTRUCT extends Structure {
public static class ByReference extends MOUSEHOOKSTRUCT implements
Structure.ByReference {
};
public POINT pt;
public HWND hwnd;
public int wHitTestCode;
public ULONG_PTR dwExtraInfo;
}
}
public static void main(String[] args) {
EventQueue.invokelater(new Runnable() {
@Override
public void run() {
try {
new MouseExample();
} catch (AWTException e) {
e.printStackTrace();
}
}
});
}
}
Solution
You should call in your thread
User32. PostQuitMessage(0)
Notifies the native thread (hook) that you no longer need it When you do, check in your code
See that you no longer need the hook and terminate it locally I suggest you try to close the hook with an internal event, such as
Just to see if it works properly
In this article: working example of JNA mouse hook, you can see some code that should be helpful to you Cheers!
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