受到这个答案的启发：
how to obtain mouse click coordinates outside my window in Java
我已经实现了一个Java Swing屏幕颜色选择器，其中几乎透明的JFrame覆盖了所有屏幕。 R，G，B值显示在三个JTextfield中，当我点击某处时，我希望将此点的颜色显示在表格中作为新的数据行。
您可以看到颜色代码已显示并正在更改，因此会触发mouseMoved()个事件，但mouseClicked() / mousePressed()事件不会触发。我很迷惑。我使用的是Windows 10。
代码在这里：
import static java.awt.GraphicsDevice.WindowTranslucency.TRANSLUCENT;
import java.awt.AWTException;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Point;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.event.MouseInputListener;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
public class ColorPicker extends JFrame{
private static JTextField fieldRed;
private static JTextField fieldGreen;
private static JTextField fieldBlue;
private Robot robot;
private static JTable table;
public JFrame helperScreen;
public ColorPicker() {
initialize();
}
private void initialize() {
setAlwaysOnTop(false);
setAutoRequestFocus(false);
setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
setLayout(new GridBagLayout());
// try {
// UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
// } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
// | UnsupportedLookAndFeelException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
GridBagConstraints c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
table = new JTable();
DefaultTableModel model = new DefaultTableModel();
model.setColumnIdentifiers(new String[] {"Keys", "Values", "Color"});
table.setModel(model);
table.setDefaultRenderer(Object.class, new ColorRenderer());
JScrollPane pane = new JScrollPane(table);
pane.setBounds(0, 0, 500, 500);
c.gridheight = 1;
c.gridwidth = 3;
c.gridx = 0;
c.gridy = 0;
add(pane, c);
c = new GridBagConstraints();
c.gridheight = 1;
c.gridwidth = 1;
c.gridx = 0;
c.gridy = 1;
c.weightx = 0.5;
fieldRed = new JTextField();
fieldRed.setPreferredSize(new Dimension(100, 25));
add(fieldRed, c);
c.gridx = 1;
fieldGreen = new JTextField();
fieldGreen.setPreferredSize(new Dimension(100, 25));
add(fieldGreen, c);
c.gridx = 2;
fieldBlue = new JTextField();
fieldBlue.setPreferredSize(new Dimension(100, 25));
add(fieldBlue, c);
Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
helperScreen = new JFrame();
helperScreen.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
helperScreen.setAlwaysOnTop(true);
helperScreen.setOpacity(0.05f);
helperScreen.setPreferredSize(Toolkit.getDefaultToolkit().getScreenSize());
helperScreen.setBounds(0, 0, (int)screen.getWidth(), (int)screen.getHeight());
helperScreen.addMouseMotionListener(new ScreenMouseListener());
helperScreen.setVisible(true);
pack();
setVisible(true);
}
public static void main(String[] args) {
// Determine if the GraphicsDevice supports translucency.
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gd = ge.getDefaultScreenDevice();
//If translucent windows aren't supported, exit.
if (!gd.isWindowTranslucencySupported(TRANSLUCENT)) {
System.err.println("Translucency is not supported");
System.exit(0);
}
JFrame.setDefaultLookAndFeelDecorated(true);
ColorPicker picker = new ColorPicker();
}
private class ColorRenderer extends DefaultTableCellRenderer {
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus,
int row, int column) {
// TODO Auto-generated method stub
if (column == 2 && value instanceof Color) {
Component label = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
label.setBackground((Color)value);
JLabel label2 = (JLabel)label;
label2.setText("");
return label2;
} else {
setBackground(Color.WHITE);
setText(value.toString());
return this;
}
}
}
private class ScreenMouseListener implements MouseInputListener {
Object[] row = new Object[3];
@Override
public void mouseClicked(MouseEvent e) {
try {
robot = new Robot();
} catch (AWTException eg) {
// TODO Auto-generated catch block
eg.printStackTrace();
}
Point point = ((MouseEvent)e).getLocationOnScreen();
int x = point.x;
int y = point.y;
helperScreen.setVisible(false);
System.out.println("Mouse Pressed at x: " + x + " y: " + y);
Color c = robot.getPixelColor(x, y);
row[0] = x;
row[1] = y;
row[2] = c;
((DefaultTableModel)(table.getModel())).addRow(row);
((DefaultTableModel)(table.getModel())).fireTableDataChanged();
helperScreen.setVisible(true);
}
@Override
public void mousePressed(MouseEvent e) {
try {
robot = new Robot();
} catch (AWTException eg) {
// TODO Auto-generated catch block
eg.printStackTrace();
}
Point point = ((MouseEvent)e).getLocationOnScreen();
int x = point.x;
int y = point.y;
helperScreen.setVisible(false);
System.out.println("Mouse Pressed at x: " + x + " y: " + y);
Color c = robot.getPixelColor(x, y);
row[0] = x;
row[1] = y;
row[2] = c;
((DefaultTableModel)(table.getModel())).addRow(row);
((DefaultTableModel)(table.getModel())).fireTableDataChanged();
helperScreen.setVisible(true);
}
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseMoved(MouseEvent e) {
try {
robot = new Robot();
} catch (AWTException eg) {
// TODO Auto-generated catch block
eg.printStackTrace();
}
Point point = ((MouseEvent)e).getLocationOnScreen();
int x = point.x;
int y = point.y;
helperScreen.setVisible(false);
Color c = robot.getPixelColor(x, y);
fieldRed.setText(Integer.toString(c.getRed()));
fieldGreen.setText(Integer.toString(c.getGreen()));
fieldBlue.setText(Integer.toString(c.getBlue()));
helperScreen.setVisible(true);
}
}
}