问题似乎出在将笔划形状分配回形状上。如果您避免这样做，请使用该应用程序。保持响应。可见
import java.awt.BasicStroke;import java.awt.event.MouseAdapter;import java.awt.Color;import java.awt.Dimension;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Point;import java.awt.Shape;import java.awt.event.MouseEvent;import java.awt.geom.Path2D;import javax.swing.*;public class PenDemoPanel extends JPanel { private Point start; private Point stop; private Shape shape; public PenDemoPanel() { setBackground(Color.white); setPreferredSize(new Dimension(600, 600)); PathListener listener = new PathListener(); addMouseListener(listener); addMouseMotionListener(listener); } public void paintComponent(Graphics gc) { super.paintComponent(gc); Graphics2D g2 = (Graphics2D) gc; if (start != null && stop != null) { BasicStroke stroke = new BasicStroke(1); Shape strokedShape = stroke.createStrokedShape(shape); g2.draw(strokedShape); g2.fill(strokedShape); } } private class PathListener extends MouseAdapter { public void mousePressed(MouseEvent event) { start = event.getPoint(); Path2D path = new Path2D.Double(); shape = path; } public void mouseDragged(MouseEvent event) { stop = event.getPoint(); Path2D path = (Path2D) shape; path.moveTo(start.x, start.y); path.lineTo(stop.x, stop.y); shape = path; start = stop; repaint(); } public void mouseReleased(MouseEvent event) { Path2D path = (Path2D) shape; try { path.closePath(); } catch(Exception ingore) { } shape = path; repaint(); } } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { PenDemoPanel shapes = new PenDemoPanel(); Jframe frame = new Jframe("PenDemo"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.getContentPane().add(shapes); frame.pack(); frame.setVisible(true); } }); }}
