Question

如何在Java中模拟按媒体键？如播放/暂停，下一个/上一个，音量控制。

C＃有VK_MEDIA_PLAY_PAUSE，VK_MEDIA_NEXT_TRACK等等。

Java具有用于处理密钥的类Robot，但没有媒体密钥。

Answer 1

我使用JNI库使用C语言编写的代码来模拟按键操作。我创建了一个.dll文件和.java文件，分别用于按“降低音量”，“提高音量”，“静音”，“上一个曲目”，“下一个曲目”和“播放/暂停曲目”媒体键。

这里是完整存储库的link，但是，我将在下面详细说明。

MediaKeys.java必须位于名为“ commands”的程序包中。

MediaKeys.dll在编译时必须与“ src”文件夹位于同一路径，或与.class文件位于同一路径。

MediaKeys.java文件包含以下内容：

package commands

public class MediaKeys {

    //loads library from "MediaKeys.dll"
    static {
        System.loadLibrary("MediaKeys");
    }



    public static native void volumeMute();

    public static native void volumeDown();

    public static native void volumeUp();


    public static native void songPrevious();

    public static native void songNext();

    public static native void songPlayPause();



    //test driver
    public static void main(String[] args) {

        //volumeMute();

    }

}

静态块加载.dll文件，然后使用native关键字声明用C编程的功能。

如果仅需要这些功能，则可以将.dll文件用于Windows。如果您需要.dll的源代码，则它包含在上面的link中，下面我将对其进行详细说明。

.dll由两个文件组成，一个是函数源代码的C文件，另一个是头文件。（分别名为MediaKeys.c和MediaKeys.h）

MediaKeys.c包含按所需键的代码。为了节省空间，仅针对“下一个曲目”，“上一个曲目”和“暂停/播放曲目”功能格式化C和头文件的以下代码块。

头文件： MediaKeys.h

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class MediaKeys */

#ifndef _Included_MediaKeys
#define _Included_MediaKeys
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     MediaKeys
 * Method:    songPrevious
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_commands_MediaKeys_songPrevious
  (JNIEnv *, jclass);

/*
 * Class:     MediaKeys
 * Method:    songNext
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_commands_MediaKeys_songNext
  (JNIEnv *, jclass);

/*
 * Class:     MediaKeys
 * Method:    songPlayPause
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_commands_MediaKeys_songPlayPause
  (JNIEnv *, jclass);

#ifdef __cplusplus
}
#endif
#endif

头文件包含以下格式的每种方法所需的语句：

JNIEXPORT void JNICALL Java_{package_name}_{class_name}_{method_name}
  (JNIEnv *, jclass);

然后，C文件必须与头文件相对应。 MediaKeys.c

//standard dependencies for C and the JNI Library
#include <jni.h>
#include <stdio.h>
#include "MediaKeys.h"

//dependencies required to hit the media keys
#define WINVER 0x0500
#include <windows.h>


//hits the previous track key
JNIEXPORT void JNICALL Java_commands_MediaKeys_songPrevious (JNIEnv *env, jobject thisObj) {

    KEYBDINPUT kbi;

    //specific keycode
    kbi.wVk = VK_MEDIA_PREV_TRACK; //this can be changed depending on the key

    kbi.wScan = 0;
    kbi.dwFlags = 0;
    kbi.time = 0;
    kbi.dwExtraInfo = (ULONG_PTR) GetMessageExtraInfo();

    INPUT input;
    input.type = INPUT_KEYBOARD;
    input.ki   = kbi;

    SendInput(1, &input, sizeof(INPUT));

    return;

}


//hits the next track key
JNIEXPORT void JNICALL Java_commands_MediaKeys_songNext (JNIEnv *env, jobject thisObj) {

    KEYBDINPUT kbi;

    //specific keycode
    kbi.wVk = VK_MEDIA_NEXT_TRACK;

    kbi.wScan = 0;
    kbi.dwFlags = 0;
    kbi.time = 0;
    kbi.dwExtraInfo = (ULONG_PTR) GetMessageExtraInfo();

    INPUT input;
    input.type = INPUT_KEYBOARD;
    input.ki   = kbi;

    SendInput(1, &input, sizeof(INPUT));

    return;

}


//hits the play/pause key
JNIEXPORT void JNICALL Java_commands_MediaKeys_songPlayPause (JNIEnv *env, jobject thisObj) {

    KEYBDINPUT kbi;

    //specific keycode
    kbi.wVk = VK_MEDIA_PLAY_PAUSE;

    kbi.wScan = 0;
    kbi.dwFlags = 0;
    kbi.time = 0;
    kbi.dwExtraInfo = (ULONG_PTR) GetMessageExtraInfo();

    INPUT input;
    input.type = INPUT_KEYBOARD;
    input.ki   = kbi;

    SendInput(1, &input, sizeof(INPUT));

    return;

}

C文件为每个标头语句包含一个对应的函数，格式如下：

JNIEXPORT void JNICALL Java_{package_name}_{class_name}_{method_name} (JNIEnv *env, jobject thisObj) {

    //specific code goes here
    return;

}

并且如代码中所述，您可以通过更改kbi.wVk = specific_key_goes_here;来更改特定键。可以找到可用键的列表here。

一旦创建了C和头文件，就可以将它们编译为dll文件。为此，我使用Code :: Blocks创建了一个新的动态链接库项目，添加了MediaKeys.c和MediaKeys.h文件，然后单击build。

由于我的JVM是64位的，而Code :: Blocks的默认编译器是32位的，因此我不得不install a 64-bit compiler进入Code :: Blocks。

您还必须添加指向jni.h库的链接。为此，请在Code :: Blocks中转到Settings>Compiler>Search Directories并添加目录C:\Program Files\Java\jdk1.8.0_171\include和C:\Program Files\Java\jdk1.8.0_171\include\win32。您很可能必须根据jdk版本更改文件路径。

一旦构建，然后将dll文件复制到Java程序所需的位置。

有关设置Java本机接口的更多信息，我发现this link特别有用。

我知道这则帖子有些陈旧，但我认为此信息可能会对其他人有所帮助。

Answer 2

创建自己的keylistener并监视任何出现的内容，然后使用此值。这是简单的KeySpy类：

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JFrame;
import javax.swing.JLabel;


public class KeySpy {
    JLabel label=new JLabel("Enter the key");
    public KeySpy() {
        JFrame frame=new JFrame("KeySpy");
        frame.add(label);

        frame.addKeyListener(new KeyListener() {

            @Override
            public void keyTyped(KeyEvent e) {
            }

            @Override
            public void keyReleased(KeyEvent e) {
            }

            @Override
            public void keyPressed(KeyEvent e) {
                label.setText(e.toString());
                System.out.println(e.toString());
            }
        });

        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        new KeySpy();

    }

}

这是键盘上2个按钮的结果

   [Stop] = java.awt.event.KeyEvent[KEY_PRESSED,keyCode=0,keyText=Unknown keyCode: 0x0,keyChar=Undefined keyChar,keyLocation=KEY_LOCATION_STANDARD,rawCode=178,primaryLevelUnicode=0,scancode=36,extendedKeyCode=0x0] on frame0

   [Mute] = java.awt.event.KeyEvent[KEY_PRESSED,keyCode=0,keyText=Unknown keyCode: 0x0,keyChar=Undefined keyChar,keyLocation=KEY_LOCATION_STANDARD,rawCode=173,primaryLevelUnicode=0,scancode=32,extendedKeyCode=0x0] on frame0

正如您所看到的，他们没有keyCode，但他们确实有rawCode - 所以请使用它。

Answer 3

我改进了Alex's KeySpy application。 JFrame保持焦点，因此您可以最小化或最大化应用程序，并且在应用程序处于焦点时仍然按任意键。

这是GUI。

KeySpy GUI

我将信息放在标签/值网格中，以便更容易找到您感兴趣的值。

这是代码。这是GridBagLayout的一个很好的例子。

package com.ggl.testing;

import java.awt.Component;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class KeySpy implements Runnable {

    private KeySpyPanel keySpyPanel;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new KeySpy());
    }

    @Override
    public void run() {
        final JFrame frame = new JFrame("Key Spy");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);
        frame.addWindowFocusListener(new WindowAdapter() {
            public void windowGainedFocus(WindowEvent e) {
                frame.requestFocusInWindow();
            }
        });

        keySpyPanel = new KeySpyPanel();
        frame.add(keySpyPanel.getPanel());
        frame.addKeyListener(new KeyPressedListener(this));

        frame.pack();
        frame.setVisible(true);
    }

    public KeySpyPanel getKeySpyPanel() {
        return keySpyPanel;
    }

    public class KeySpyPanel {

        private final Insets bottomInsets = new Insets(10, 10, 10, 10);
        private final Insets normalInsets = new Insets(10, 10, 0, 10);

        private JPanel panel;

        private JTextField keyCodeField;
        private JTextField keyTextField;
        private JTextField keyCharField;
        private JTextField keyLocationField;
        private JTextField modifiersField;
        private JTextField extModifiersField;
        private JTextField rawCodeField;
        private JTextField primaryLevelUnicodeField;
        private JTextField scancodeField;
        private JTextField extendedKeyCodeField;

        public KeySpyPanel() {
            createPartControl();
        }

        private void createPartControl() {
            panel = new JPanel();
            panel.setLayout(new GridBagLayout());

            int gridy = 0;

            JLabel anyKeyLabel = new JLabel("Press any key");
            anyKeyLabel.setFont(anyKeyLabel.getFont().deriveFont(36F));
            anyKeyLabel.setHorizontalAlignment(JLabel.CENTER);
            addComponent(panel, anyKeyLabel, 0, gridy++, 2, 1, normalInsets,
                    GridBagConstraints.CENTER, GridBagConstraints.HORIZONTAL);

            JLabel keyCodeLabel = new JLabel("KeyCode:");
            addComponent(panel, keyCodeLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            keyCodeField = new JTextField(20);
            keyCodeField.setEditable(false);
            addComponent(panel, keyCodeField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel keyTextLabel = new JLabel("KeyText:");
            addComponent(panel, keyTextLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            keyTextField = new JTextField(20);
            keyTextField.setEditable(false);
            addComponent(panel, keyTextField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel keyCharLabel = new JLabel("KeyChar:");
            addComponent(panel, keyCharLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            keyCharField = new JTextField(20);
            keyCharField.setEditable(false);
            addComponent(panel, keyCharField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel keyLocationLabel = new JLabel("KeyLocation:");
            addComponent(panel, keyLocationLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            keyLocationField = new JTextField(20);
            keyLocationField.setEditable(false);
            addComponent(panel, keyLocationField, 1, gridy++, 1, 1,
                    normalInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel modifiersLabel = new JLabel("Modifiers:");
            addComponent(panel, modifiersLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            modifiersField = new JTextField(20);
            modifiersField.setEditable(false);
            addComponent(panel, modifiersField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel extModifiersLabel = new JLabel("ExtModifiers:");
            addComponent(panel, extModifiersLabel, 0, gridy, 1, 1,
                    normalInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            extModifiersField = new JTextField(20);
            extModifiersField.setEditable(false);
            addComponent(panel, extModifiersField, 1, gridy++, 1, 1,
                    normalInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel rawCodeLabel = new JLabel("RawCode:");
            addComponent(panel, rawCodeLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            rawCodeField = new JTextField(20);
            rawCodeField.setEditable(false);
            addComponent(panel, rawCodeField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel primaryLevelUnicodeLabel = new JLabel("PrimaryLevelUnicode:");
            addComponent(panel, primaryLevelUnicodeLabel, 0, gridy, 1, 1,
                    normalInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            primaryLevelUnicodeField = new JTextField(20);
            primaryLevelUnicodeField.setEditable(false);
            addComponent(panel, primaryLevelUnicodeField, 1, gridy++, 1, 1,
                    normalInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel scancodeLabel = new JLabel("Scancode:");
            addComponent(panel, scancodeLabel, 0, gridy, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            scancodeField = new JTextField(20);
            scancodeField.setEditable(false);
            addComponent(panel, scancodeField, 1, gridy++, 1, 1, normalInsets,
                    GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            JLabel extendedKeyCodeLabel = new JLabel("ExtendedKeyCode:");
            addComponent(panel, extendedKeyCodeLabel, 0, gridy, 1, 1,
                    bottomInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);

            extendedKeyCodeField = new JTextField(20);
            extendedKeyCodeField.setEditable(false);
            addComponent(panel, extendedKeyCodeField, 1, gridy++, 1, 1,
                    bottomInsets, GridBagConstraints.LINE_START,
                    GridBagConstraints.HORIZONTAL);
        }

        private void addComponent(Container container, Component component,
                int gridx, int gridy, int gridwidth, int gridheight,
                Insets insets, int anchor, int fill) {
            GridBagConstraints gbc = new GridBagConstraints(gridx, gridy,
                    gridwidth, gridheight, 1.0D, 1.0D, anchor, fill, insets, 0,
                    0);
            container.add(component, gbc);
        }

        public JPanel getPanel() {
            return panel;
        }

        public void setKeyPressed(KeyEvent event) {
            String s = event.toString();

            keyCodeField.setText(getValue("keyCode", s));
            keyTextField.setText(getValue("keyText", s));
            keyCharField.setText(getValue("keyChar", s));
            keyLocationField.setText(getValue("keyLocation", s));
            modifiersField.setText(getValue("modifiers", s));
            extModifiersField.setText(getValue("extModifiers", s));
            rawCodeField.setText(getValue("rawCode", s));
            primaryLevelUnicodeField
                    .setText(getValue("primaryLevelUnicode", s));
            scancodeField.setText(getValue("scancode", s));
            extendedKeyCodeField.setText(getValue("extendedKeyCode", s));
        }

        private String getValue(String key, String line) {
            int sPos = line.indexOf(key);
            if (sPos >= 0) {
                int nPos = sPos + key.length() + 1;
                int ePos = line.indexOf(",", nPos);
                if (ePos < 0) {
                    ePos = line.indexOf("]", nPos);
                }
                if (ePos >= 0) {
                    return line.substring(nPos, ePos);
                }
            }

            return "";
        }

    }

    public class KeyPressedListener extends KeyAdapter {

        private KeySpy keySpyFrame;

        public KeyPressedListener(KeySpy keySpyFrame) {
            this.keySpyFrame = keySpyFrame;
        }

        @Override
        public void keyPressed(KeyEvent event) {
            keySpyFrame.getKeySpyPanel().setKeyPressed(event);
        }
    }

}

Answer 4

您可以使用https://github.com/kwhat/jnativehook来实现它，然后监视密钥。在my question我已经写了一些示例方法：

public static void MediaKeyForward(){
    GlobalScreen.postNativeEvent(new NativeKeyEvent(2401,0,176,57369,org.jnativehook.keyboard.NativeKeyEvent.CHAR_UNDEFINED));

}
public static void MediaKeyBack(){
    GlobalScreen.postNativeEvent(new NativeKeyEvent(2401,0,177,57360,org.jnativehook.keyboard.NativeKeyEvent.CHAR_UNDEFINED));

}
public static void MediaKeyPause(){
 GlobalScreen.postNativeEvent(new NativeKeyEvent(2401,0,179,57378,org.jnativehook.keyboard.NativeKeyEvent.CHAR_UNDEFINED));

}

要做的就是将库包含在项目中。可以找到如何监视密钥并获取创建密钥事件的必要参数的示例here。

如何在Java中模拟按媒体键？

4 个答案: