用Java JNA编写的键侦听器.防止多次回拨 [英] Key listener written in Java JNA. Prevent multiple Callback

问题描述

我使用以下代码侦听全局键事件: Win32HookManager.java

I use the following code to listen to global key events: Win32HookManager.java

import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.Kernel32;
import com.sun.jna.platform.win32.User32;
import com.sun.jna.platform.win32.WinDef.HMODULE;
import com.sun.jna.platform.win32.WinDef.LRESULT;
import com.sun.jna.platform.win32.WinDef.WPARAM;
import com.sun.jna.platform.win32.WinDef.LPARAM;
import com.sun.jna.platform.win32.WinUser;
import com.sun.jna.platform.win32.WinUser.HHOOK;
import com.sun.jna.platform.win32.WinUser.KBDLLHOOKSTRUCT;
import com.sun.jna.platform.win32.WinUser.LowLevelKeyboardProc;
import com.sun.jna.platform.win32.WinUser.MSG;

/** Sample implementation of a low-level keyboard hook on W32. */
public class KeyHook {
    private static volatile boolean quit;
    private static HHOOK hhk;
    private static LowLevelKeyboardProc keyboardHook;

    public static void main(String[] args) {
        final User32 lib = User32.INSTANCE;
        HMODULE hMod = Kernel32.INSTANCE.GetModuleHandle(null);
        keyboardHook = new LowLevelKeyboardProc() {
            @Override
            public LRESULT callback(int nCode, WPARAM wParam, KBDLLHOOKSTRUCT info) {
                if (nCode >= 0) {
                    switch(wParam.intValue()) {
                    case WinUser.WM_KEYUP:
                    case WinUser.WM_KEYDOWN:
                    case WinUser.WM_SYSKEYUP:
                    case WinUser.WM_SYSKEYDOWN:
                        System.err.println("in callback, key=" + info.vkCode);
                        if (info.vkCode == 81) {
                            quit = true;
                        }
                    }
                }

                Pointer ptr = info.getPointer();
                long peer = Pointer.nativeValue(ptr);
                return lib.CallNextHookEx(hhk, nCode, wParam, new LPARAM(peer));
            }
        };
        hhk = lib.SetWindowsHookEx(WinUser.WH_KEYBOARD_LL, keyboardHook, hMod, 0);
        System.out.println("Keyboard hook installed, type anywhere, 'q' to quit");
        new Thread() {
            @Override
            public void run() {
                while (!quit) {
                    try { Thread.sleep(10); } catch(Exception e) { }
                }
                System.err.println("unhook and exit");
                lib.UnhookWindowsHookEx(hhk);
                System.exit(0);
            }
        }.start();

        // This bit never returns from GetMessage
        int result;
        MSG msg = new MSG();
        while ((result = lib.GetMessage(msg, null, 0, 0)) != 0) {
            if (result == -1) {
                System.err.println("error in get message");
                break;
            }
            else {
                System.err.println("got message");
                lib.TranslateMessage(msg);
                lib.DispatchMessage(msg);
            }
        }
        lib.UnhookWindowsHookEx(hhk);
    }
}

我想知道为什么一次按下回调键两次，我们如何防止它呢?这是一个按键的示例.

i am wondering why the callback key called twice time if we press it one time and how we can prevent it?is it possible.This is an example of a single keypress.

in callback, key= 70
in callback, key= 70

我不确定我是否有权在此主题中提出另一个问题，但问题是第一个问题要结束，并且我不想创建另一个主题.那么为什么我们得到键码= 70而不是VC_F = 0x0021.有什么办法只能得到VC_F代码

I am not sure if i had the permission to ask another question in this topic but the question is to close with the first one and i don't want to create an another topic. so Why we got keycode=70 instead of VC_F = 0x0021. is any way to got only the VC_F code

VC_F = 0x0021;

推荐答案

程序正在监听几条消息:WM_KEYUP和WM_KEYDOWN

The program are listening for several messages: WM_KEYUP and WM_KEYDOWN

您应该只听WM_KEYDOWN.

You should listen only for WM_KEYDOWN.

相关问题:键盘输入和Win32消息循环

MSDN信息: https ://msdn.microsoft.com/zh-CN/library/windows/desktop/ms646280(v = vs.85).aspx

如果您需要更复杂的行为，则应存储一些信息，并查看是否将接收连续的消息.

If you need a more complicated behavior then you should store some info and see for successive messages to be received.

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