屏幕上任何位置的Java鼠标移动

Question

我敢肯定这是可能的，但是我所有的搜索都空白了。

在Java中，是否可以在Java应用程序之外注册鼠标移动事件？因此，如果鼠标指针移动到屏幕上的任何地方，我都会回电。轮询可能是近似值，MouseInfo.getPointerInfo但必须有更好的方法。

谢谢

解释用例：它仅用于一个宠物项目，但是基本上是当鼠标击中屏幕边缘时触发事件。我还认为，如果您尝试 超越
屏幕边缘，可能会触发其他事件。为此，我认为鼠标运动侦听器可能更合适。

Answer 1

java.awt.event.MouseMotionListener只会为您提供有关鼠标在应用程序窗口内移动的信息。对于在该窗口外发生的事件，没有办法解决MouseInfo.getPointerInfo。但是，您可以编写一个（可能是单例的）类，该类定期轮询指针信息并允许MouseMotionListeners添加：

import java.awt.Component;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.util.HashSet;
import java.util.Set;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

/**
 * This class checks the position every #DELAY milliseconds and 
 * informs all registered MouseMotionListeners about position updates.
 */
public class MouseObserver {
    /* the resolution of the mouse motion */
    private static final int DELAY = 10;

    private Component component;
    private Timer timer;
    private Set<MouseMotionListener> mouseMotionListeners;

    protected MouseObserver(Component component) {
        if (component == null) {
            throw new IllegalArgumentException("Null component not allowed.");
        }

        this.component = component;

        /* poll mouse coordinates at the given rate */
        timer = new Timer(DELAY, new ActionListener() {
                private Point lastPoint = MouseInfo.getPointerInfo().getLocation();

                /* called every DELAY milliseconds to fetch the
                 * current mouse coordinates */
                public synchronized void actionPerformed(ActionEvent e) {
                    Point point = MouseInfo.getPointerInfo().getLocation();

                    if (!point.equals(lastPoint)) {
                        fireMouseMotionEvent(point);
                    }

                    lastPoint = point;
                }
            });
        mouseMotionListeners = new HashSet<MouseMotionListener>();
    }

    public Component getComponent() {
        return component;
    }

    public void start() {
        timer.start();
    }

    public void stop() {
        timer.stop();
    }

    public void addMouseMotionListener(MouseMotionListener listener) {
        synchronized (mouseMotionListeners) {
            mouseMotionListeners.add(listener);
        }
    }

    public void removeMouseMotionListener(MouseMotionListener listener) {
        synchronized (mouseMotionListeners) {
            mouseMotionListeners.remove(listener);
        }
    }

    protected void fireMouseMotionEvent(Point point) {
        synchronized (mouseMotionListeners) {
            for (final MouseMotionListener listener : mouseMotionListeners) {
                final MouseEvent event =
                    new MouseEvent(component, MouseEvent.MOUSE_MOVED, System.currentTimeMillis(),
                                   0, point.x, point.y, 0, false);

                SwingUtilities.invokeLater(new Runnable() {
                        public void run() {
                            listener.mouseMoved(event);
                        }
                    });
            }
        }
    }

    /* Testing the ovserver */
    public static void main(String[] args) {
        JFrame main = new JFrame("dummy...");
        main.setSize(100,100);
        main.setVisible(true);

        MouseObserver mo = new MouseObserver(main);
        mo.addMouseMotionListener(new MouseMotionListener() {
                public void mouseMoved(MouseEvent e) {
                    System.out.println("mouse moved: " + e.getPoint());
                }

                public void mouseDragged(MouseEvent e) {
                    System.out.println("mouse dragged: " + e.getPoint());
                }
            });

        mo.start();
    }
}

请注意，尽管与标准的MouseMotionListener有一些明显的不同：

• 您只会收到mouseMoved事件，不会收到mouseDragged事件。这是因为无法在主窗口之外接收有关单击的信息。
• 由于类似的原因，modifiers每个的MouseEvent始终为0。
• 这同样适用于价值观clickCount，popupTrigger，button
• 您将需要提供一个java.awt.Component将用作MouseEvents （伪）源的虚拟对象- null此处不允许使用值。