尝试
image在
ImageIcon更新后包装内部。同样，
Graphics#dispose当您完成对图形上下文的渲染时，还应该调用。
public void jButton1_ActionPerformed(ActionEvent evt) { BufferedImage image=new BufferedImage(jPanel1.getWidth(), jPanel1.getHeight(), BufferedImage.TYPE_3BYTE_BGR); Graphics2D g = image.createGraphics(); g.fillRect(0, 0, image.getWidth(), image.getHeight()); g.setColor(Color.BLUE); g.drawLine(0, 0, 300, 400); g.dispose(); JLabel l=new JLabel(new ImageIcon(image)); jPanel1.add(l); }您还应该依靠布局管理器，而不是自己动手做，这只会使您的生活更轻松。
就个人而言，我认为将其直接绘制到自定义组件会更容易
JPanel。查看执行自定义绘画以获取更多详细信息
用示例更新
基本上，我将您的示例更改为
- 使用布局管理器
- 在EDT上下文中加载UI
revalidate
的jPanel1
public class BadLabel extends Jframe { // start attributes private JPanel jPanel1 = new JPanel(new BorderLayout(), true); private JButton jButton1 = new JButton(); private JButton jButton2 = new JButton(); // end attributes public BadLabel(String title) { // frame-Init super(title); setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE); int frameWidth = 300; int frameHeight = 300; setSize(frameWidth, frameHeight); Dimension d = Toolkit.getDefaultToolkit().getScreenSize(); int x = (d.width - getSize().width) / 2; int y = (d.height - getSize().height) / 2; setLocation(x, y); // setResizable(false); Container cp = getContentPane(); // cp.setLayout(null); // start components // jPanel1.setBounds(48, 24, 209, 145); jPanel1.setOpaque(true); jPanel1.setBackground(Color.RED); cp.add(jPanel1); JPanel buttons = new JPanel(); // jButton1.setBounds(88, 208, 75, 25); jButton1.setText("jButton1"); jButton1.setMargin(new Insets(2, 2, 2, 2)); jButton1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { jButton1_ActionPerformed(evt); } }); buttons.add(jButton1); // jButton2.setBounds(184, 208, 75, 25); jButton2.setText("jButton2"); jButton2.setMargin(new Insets(2, 2, 2, 2)); jButton2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { jButton2_ActionPerformed(evt); } }); buttons.add(jButton2); // end components cp.add(buttons, BorderLayout.SOUTH); setVisible(true); } // end of public BadLabel // start methods public void jButton1_ActionPerformed(ActionEvent evt) { BufferedImage image = new BufferedImage(jPanel1.getWidth(), jPanel1.getHeight(), BufferedImage.TYPE_3BYTE_BGR); Graphics2D g = image.createGraphics(); g.fillRect(0, 0, image.getWidth(), image.getHeight()); g.setColor(Color.BLUE); g.drawLine(0, 0, 300, 400); g.dispose(); JLabel l = new JLabel(new ImageIcon(image)); l.setBorder(new LineBorder(Color.BLUE)); jPanel1.add(l); jPanel1.revalidate(); } // end of jButton1_ActionPerformed public void jButton2_ActionPerformed(ActionEvent evt) { // TODO add your pre here } // end of jButton2_ActionPerformed // end methods public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (Exception exp) { } new BadLabel("BadLabel"); } }); } // end of main } // end of class BadLabel}
