How to Continuously Monitor Keystrokes in Java?-javaTutorial-php.cn

How to Continuously Monitor Keystrokes in Java?

Susan Sarandon

Release： 2024-12-11 11:41:17

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How to Continuously Monitor Keystrokes in Java?

How to Monitor Keystrokes in Java

In Java, detecting keystrokes involves "listening" to KeyEvents rather than explicitly checking if a specific key is pressed. Here's how you can achieve continuous keystroke monitoring:

In pseudocode, your desired functionality translates to:

if (isPressing("w")) {
   // perform an action
}

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Implementing Keystroke Monitoring:

To monitor keystrokes, you need to register a KeyEventDispatcher. Here's an implementation:

import java.awt.KeyEventDispatcher;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;

public class IsKeyPressed {
    private static volatile boolean wPressed = false;
    public static boolean isWPressed() {
        synchronized (IsKeyPressed.class) {
            return wPressed;
        }
    }

    public static void main(String[] args) {
        KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {

            @Override
            public boolean dispatchKeyEvent(KeyEvent ke) {
                synchronized (IsKeyPressed.class) {
                    switch (ke.getID()) {
                    case KeyEvent.KEY_PRESSED:
                        if (ke.getKeyCode() == KeyEvent.VK_W) {
                            wPressed = true;
                        }
                        break;

                    case KeyEvent.KEY_RELEASED:
                        if (ke.getKeyCode() == KeyEvent.VK_W) {
                            wPressed = false;
                        }
                        break;
                    }
                    return false;
                }
            }
        });
    }
}

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Usage:

Once the KeyEventDispatcher is registered, you can check the state of a key using:

if (IsKeyPressed.isWPressed()) {
    // take desired action
}

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Multiple Keys:

To monitor multiple keys, you can extend the IsKeyPressed class to include a map of keys and their respective states.

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