好的，所以我浏览了多个论坛和Google，找不到针对我特定问题的答案。因此，我有两个面板堆叠在一起，一个面板是glassPane。当您在glassPane上拖动鼠标时，它会在光标上绘制一条垂直的红线，但是可以，但是当我单击glassPane时，我希望它在glassPane下方的面板上的光标位置绘制一条黑线。我可以将它重定向到底部面板，但它不会画线。只是使红线消失，直到再次移动鼠标。另外，如果我将glassPane设置为不可见，然后单击底部面板，则会画出线条，因此绘图代码可以正常工作。提前致谢。
主班
import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Robot;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Line2D;
import java.awt.event.MouseMotionAdapter;
import java.util.ArrayList;
public class LiveField extends JPanel {
/**
* Create the panel.
*/
static JFrame frame;
static JPanel ContentPane;
private JPanel panel;
private MyGlassPane glassPane;
public static void main(String[] args) throws AWTException
{
LiveField live = new LiveField();
frame.setVisible(true);
}
public LiveField() throws AWTException {
frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1000, 433);
setLayout(new BorderLayout(0, 0));
ContentPane = new JPanel();
frame.setContentPane(ContentPane);
ContentPane.setLayout(new BorderLayout(0, 0));
panel = new JPanel()
{
public void paintComponent(Graphics g) {
super.paintComponent(g);
panel.setBackground(new Color(50,160,55));
}
};
glassPane = new MyGlassPane(panel);
frame.setGlassPane(glassPane);
glassPane.setVisible(true);
panel.addMouseListener(new MouseAdapter() {
int[] pos = new int[2];
@Override
public void mouseClicked(MouseEvent e) {
System.out.println("Handles click event");
Graphics g = panel.getGraphics();
g.setColor(new Color(50,165,55));
g.drawLine(pos[0], pos[1], 0+pos[0], 0);//to top
g.drawLine(pos[0], pos[1], 0+pos[0], panel.getHeight());//to bottom
int y = e.getYOnScreen();
int x = e.getXOnScreen();
pos[0]= x;
pos[1] = y;
g.setColor(new Color(0,0,0));
g.drawLine(x, y, 0+x, 0);//to top
g.drawLine(x, y, 0+x, panel.getHeight());//to bottom
g.dispose();
}
});
ContentPane.add(panel, BorderLayout.CENTER);
}
GlassPane类
import java.awt.AWTException;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Robot;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;
import javax.swing.JComponent;
class MyGlassPane extends JComponent implements ItemListener {
Point point;
protected void paintComponent(Graphics g) {
}
public void setPoint(Point p) {
point = p;
}
public MyGlassPane(final Container contentPane) throws AWTException {
final Component glass = this;
addMouseMotionListener(new MouseMotionListener()
{
ArrayList<Integer> line = new ArrayList<Integer>();
Robot rb = new java.awt.Robot();
@Override
public void mouseMoved(MouseEvent e) {
//System.out.println("Moving");
Graphics g = glass.getGraphics();
if(!line.isEmpty())
{
//System.out.println("line is not empty");
g.setColor(new Color(50,160,55));
g.drawLine(line.get(0), line.get(1), 0+line.get(0), 0);//to top
g.drawLine(line.get(0), line.get(1), 0+line.get(0), contentPane.getHeight());//to bottom
}
//System.out.println("draw line");
int x = e.getXOnScreen();
int y = e.getYOnScreen();
Color col = rb.getPixelColor(x, y);
//System.out.println(col.toString() + " : " + Color.white.toString());
//System.out.println(col.equals(new Color(255,255,255)));
if(!col.equals(new Color(255,255,255)) && !inEndZone(x))
{
g.setColor(new Color(255,0,0));
line = new ArrayList<Integer>();
line.add(x);line.add(y);
g.drawLine(x, y, 0+line.get(0), 0);//to top
g.drawLine(x, y, 0+line.get(0), contentPane.getHeight());//to bottom
}
g.dispose();
}
private boolean inEndZone(int x) {
int ends = contentPane.getWidth()/10;
//System.out.println(x + " : " + ends);
if(x<ends)
{
//System.out.println("In endzone");
return true;
}
else if(x>contentPane.getWidth()-ends)
{
return true;
}
else
{
return false;
}
}
@Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
}
});
addMouseListener(new CBListener(this,contentPane));
}
@Override
public void itemStateChanged(ItemEvent e) {
// TODO Auto-generated method stub
setVisible(e.getStateChange() == ItemEvent.SELECTED);
}
}
侦听器类（用于调度鼠标单击）
import java.awt.Component;
import java.awt.Container;
import java.awt.Point;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import javax.swing.SwingUtilities;
import javax.swing.event.MouseInputAdapter;
class CBListener extends MouseInputAdapter {
Toolkit toolkit;
Robot rb;
MyGlassPane glassPane;
Container contentPane;
public CBListener(MyGlassPane glassPane, Container contentPane) {
toolkit = Toolkit.getDefaultToolkit();
this.glassPane = glassPane;
this.contentPane = contentPane;
}
@Override
public void mouseClicked(MouseEvent e) {
redispatchMouseEvent(e, false);
}
// A basic implementation of redispatching events.
private void redispatchMouseEvent(MouseEvent e, boolean repaint) {
Point glassPanePoint = e.getPoint();
Container container = contentPane;
Point containerPoint = SwingUtilities.convertPoint(glassPane,
glassPanePoint, contentPane);
if (containerPoint.y < 0) { // we're not in the content pane
} else {
// The mouse event is probably over the content pane.
// Find out exactly which component it's over.
Component component = SwingUtilities.getDeepestComponentAt(
container, containerPoint.x, containerPoint.y);
if ((component != null) && (component.equals(contentPane))) {
System.out.println("contentPane");
// Forward events over the check box.
Point componentPoint = SwingUtilities.convertPoint(glassPane,
glassPanePoint, component);
component.dispatchEvent(new MouseEvent(component, e.getID(), e
.getWhen(), e.getModifiers(), componentPoint.x,
componentPoint.y, e.getClickCount(), e
.isPopupTrigger()));
}
}
// Update the glass pane if requested.
if (repaint) {
glassPane.setPoint(glassPanePoint);
glassPane.repaint();
}
}
}
最佳答案
我可以将鼠标单击重定向到底部面板，但是它
不会画线。它只会使红线消失，直到您移动
再次鼠标
不，确实在画黑线。但是该线是在红线上方绘制的，这使红线消失，直到再次移动鼠标为止。我猜你正在寻找这样的东西：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class DoublePanel extends JFrame
{
JPanel mainPanel;
int x1;
public void prepareAndShowGUI()
{
setTitle("DoublePanel");
mainPanel = new JPanel()
{
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.BLACK);
g.drawLine(x1,0,x1,this.getHeight());
}
};
mainPanel.setBackground(new Color(50,160,55));
mainPanel.setLayout(new BorderLayout());
mainPanel.add(new upperPanel(this));
setContentPane(mainPanel);
setSize(500,600);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setVisible(true);
}
public void setXValue(int x)
{
this.x1 = x;
mainPanel.repaint();
}
class upperPanel extends JPanel
{
int x; int y;
DoublePanel dp;
upperPanel(DoublePanel d)
{
this.dp = d;
setOpaque(false);
addMouseMotionListener(new MouseAdapter()
{
@Override
public void mouseMoved(MouseEvent evt)
{
x = evt.getX();
y = evt.getY();
repaint();
}
});
addMouseListener(new MouseAdapter()
{
@Override
public void mouseClicked(MouseEvent evt)
{
dp.setXValue(evt.getX());
}
});
}
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.RED);
g.drawLine(x,0,x,this.getHeight());
}
}
public static void main(String st[])
{
SwingUtilities.invokeLater( new Runnable()
{
public void run()
{
DoublePanel dp = new DoublePanel();
dp.prepareAndShowGUI();
}
});
}
}
关于java - 单击GlassPane时在GlassPane后面的JPanel上绘图，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/15367232/