我创建了一个MouseMotionDetection类,该角色只是检测用户是否已将鼠标移动到屏幕上的任何位置.
为此我在我的类构造函数中创建了一个新的JFrame,其屏幕大小是不可见的,所以基本上我在整个屏幕上观察鼠标运动.
但是,我有一个奇怪的错误：
在代码的当前形式中,一旦激活此类,我只检测到一个鼠标移动而没有其他任何东西,它在此之后就会停止工作.但是,如果我将设置帧backfround的行放在注释中的0f,0f,0f(透明)然后激活,整个屏幕变为灰色,我会按照我的需要跟踪所有鼠标动作(我只是可以看不到任何东西.
我真的不明白为什么会发生这种情况,没有看到相关问题,也没有相关的javadoc,which discusses MouseMotion events.
这是代码：
public class MouseMotionDetection extends JPanel
implements MouseMotionListener{
public MouseMotionDetection(Region tableRegion,Observer observer){
addMouseMotionListener(this);
setBackground(new Color(0f,0f));
JFrame frame = new JFrame();
frame.setUndecorated(true);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
frame.setSize(screenSize);
frame.setBackground(new Color(0f,0f));
frame.setDefaultCloSEOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setAlwaysOnTop(true);
JComponent contentPane = this;
contentPane.setOpaque(true);
frame.getContentPane().add(contentPane,BorderLayout.CENTER);
frame.setVisible(true);
}
@Override
public void mouseDragged(MouseEvent arg0) {
}
@Override
public void mouseMoved(MouseEvent arg0) {
System.out.println("mouse movement detected");
}
解决方法
完全透明的框架不会接收鼠标事件.
这是使用MouseInfo的替代方法.这适用于应用程序的组件.是不可见的(透明的),未聚焦的或最小化的.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.GeneralPath;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class MouseMoveOnScreen {
Robot robot;
JLabel label;
GeneralPath gp;
Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
MouseMoveOnScreen() throws AWTException {
robot = new Robot();
label = new JLabel();
gp = new GeneralPath();
Point p = MouseInfo.getPointerInfo().getLocation();
gp.moveTo(p.x,p.y);
drawLatestMouseMovement();
ActionListener al = new ActionListener() {
Point lastPoint;
@Override
public void actionPerformed(ActionEvent e) {
Point p = MouseInfo.getPointerInfo().getLocation();
if (!p.equals(lastPoint)) {
gp.lineTo(p.x,p.y);
drawLatestMouseMovement();
}
lastPoint = p;
}
};
Timer timer = new Timer(40,al);
timer.start();
}
public void drawLatestMouseMovement() {
BufferedImage biOrig = robot.createScreenCapture(
new Rectangle(0,d.width,d.height));
BufferedImage small = new BufferedImage(
biOrig.getWidth() / 4,biOrig.getHeight() / 4,BufferedImage.TYPE_INT_RGB);
Graphics2D g = small.createGraphics();
g.scale(.25,.25);
g.drawImage(biOrig,label);
g.setStroke(new BasicStroke(8));
g.setColor(Color.RED);
g.draw(gp);
g.dispose();
label.setIcon(new ImageIcon(small));
}
public JComponent getUI() {
return label;
}
public static void main(String[] args) throws Exception {
Runnable r = new Runnable() {
@Override
public void run() {
JPanel ui = new JPanel(new BorderLayout(2,2));
ui.setBorder(new EmptyBorder(4,4,4));
try {
MouseMoveOnScreen mmos = new MouseMoveOnScreen();
ui.add(mmos.getUI());
} catch (AWTException ex) {
ex.printStackTrace();
}
JFrame f = new JFrame("Track Mouse On Screen");
// quick hack to end the frame and timer
f.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
f.setContentPane(ui);
f.pack();
f.setLocationByPlatform(true);
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
