再次更新JFrame

1. Simpy使用CardLayout来交换视图。
2. 请使用Swing计时器，而不要使用当前的后台线程，因为您当前的代码对Swing线程而言并不安全，并且存在发生危险的不可预测的线程异常的风险。
3. 我会给主JPanel CardLayout，然后添加一个JLabel来保存带有合适的String常量的JPanel。
4. 然后，我将使用JPanel添加到主CardLayout中，将一个空的JLabel添加到add方法中的另一个String常量中。即

   add(new JLabel(), BLANK_COMPONENT);

5. 然后，在Swing Timer中，只需调用

   next()

   CardLayout对象，传入使用CardLayout的主要组件：

   cardLayout.next(myMainJPanel);

例如，

import java.awt.CardLayout;import java.awt.Dimension;import java.awt.event.*;import javax.swing.*;public class RepaintTest extends JPanel {   private static final int PREF_W = 400;   private static final int PREF_H = PREF_W;   private static final int LABEL_COUNT = 3;   private static final String LABEL_PANEL = "label panel";   private static final Object BLANK_COMPonENT = "blank component";   private static final int TIMER_DELAY = 2000;   private CardLayout cardLayout = new CardLayout();   public RepaintTest() {      JPanel labelPanel = new JPanel();      for (int i = 0; i < LABEL_COUNT; i++) {         labelPanel.add(new JLabel("Label " + (i + 1)));      }      setLayout(cardLayout);      add(labelPanel, LABEL_PANEL);      add(new JLabel(), BLANK_COMPONENT);      new Timer(TIMER_DELAY, new TimerListener()).start();   }   @Override   public Dimension getPreferredSize() {      return new Dimension(PREF_W, PREF_H);   }   private class TimerListener implements ActionListener {      @Override      public void actionPerformed(ActionEvent e) {         cardLayout.next(RepaintTest.this);      }   }   private static void createAndShowGui() {      RepaintTest mainPanel = new RepaintTest();      Jframe frame = new Jframe("RepaintTest");      frame.setDefaultCloseOperation(Jframe.DISPOSE_ON_CLOSE);      frame.getContentPane().add(mainPanel);      frame.pack();      frame.setLocationByPlatform(true);      frame.setVisible(true);   }   public static void main(String[] args) {      SwingUtilities.invokeLater(new Runnable() {         public void run() { createAndShowGui();         }      });   }}