如何在Java/Swing中使用JLabel制作动画？

我有一个Java课程的期末项目，它是青蛙跳跃游戏。这是描述它的视频：

https://www.youtube.com/watch?v=NxWWP9cK24o https://www.youtube.com/watch?v=NxWWP9cK24o

我不知道如何使用Timer，我只知道Thread.sleep。但这不起作用。

这是我的代码：

import java.awt.event.ActionListener;
import javax.swing.Timer;




/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author gamekvnn
 */
public class FrogGame extends javax.swing.JFrame {
    /**
     * Creates new form ba
     */

    public FrogGame() {
        initComponents();
    }
        Timer time;
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        frog1 = new javax.swing.JLabel();
        frog2 = new javax.swing.JLabel();
        frog3 = new javax.swing.JLabel();
        fr0g2 = new javax.swing.JLabel();
        fr0g1 = new javax.swing.JLabel();
        fr0g3 = new javax.swing.JLabel();
        jButton1 = new javax.swing.JButton();
        background = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setLayout(null);

        frog1.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog1.png")); // NOI18N
        jPanel1.add(frog1);
        frog1.setBounds(10, 310, 80, 80);

        frog2.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog1.png")); // NOI18N
        jPanel1.add(frog2);
        frog2.setBounds(110, 310, 80, 80);

        frog3.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog1.png")); // NOI18N
        jPanel1.add(frog3);
        frog3.setBounds(210, 310, 80, 80);

        fr0g2.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog2.png")); // NOI18N
        jPanel1.add(fr0g2);
        fr0g2.setBounds(510, 310, 80, 80);

        fr0g1.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog2.png")); // NOI18N
        jPanel1.add(fr0g1);
        fr0g1.setBounds(610, 310, 80, 80);

        fr0g3.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/frog2.png")); // NOI18N
        jPanel1.add(fr0g3);
        fr0g3.setBounds(410, 310, 80, 80);

        jButton1.setText("Start");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });
        jPanel1.add(jButton1);
        jButton1.setBounds(520, 20, 100, 29);

        background.setIcon(new javax.swing.ImageIcon("/home/gamekvnn/NetBeansProjects/Project/src/UZKEjzG.png")); // NOI18N
        jPanel1.add(background);
        background.setBounds(0, 0, 710, 440);
        background.getAccessibleContext().setAccessibleName("background");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, 708, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, 442, Short.MAX_VALUE)
        );

        pack();
    }// </editor-fold>                        

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:

        frog3.setLocation(frog3.getX()+100, frog3.getY());
        repaint();
        try {
            Thread.sleep(100);;                 //1000 milliseconds is one second.
        } catch(InterruptedException ex) {
            Thread.currentThread().interrupt();
        }
        fr0g3.setLocation(fr0g3.getX()-200, fr0g3.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g2.setLocation(fr0g2.getX()-100, fr0g2.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog3.setLocation(frog3.getX()+200, frog3.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog2.setLocation(frog2.getX()+200, frog2.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog1.setLocation(frog1.getX()+100, frog1.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g3.setLocation(fr0g3.getX()-200, fr0g3.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g2.setLocation(fr0g2.getX()-200, fr0g2.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g1.setLocation(fr0g1.getX()-200, fr0g1.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog3.setLocation(frog3.getX()+100, frog3.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog2.setLocation(frog2.getX()+200, frog2.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog1.setLocation(frog1.getX()+200, frog1.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g2.setLocation(fr0g2.getX()-100, fr0g2.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        fr0g1.setLocation(fr0g1.getX()-200, frog1.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        frog1.setLocation(frog1.getX()+100, frog1.getY());
        repaint();
        try {
            Thread.sleep(100);;
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(FrogGame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(FrogGame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(FrogGame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(FrogGame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new FrogGame().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel background;
    private javax.swing.JLabel fr0g1;
    private javax.swing.JLabel fr0g2;
    private javax.swing.JLabel fr0g3;
    private javax.swing.JLabel frog1;
    private javax.swing.JLabel frog2;
    private javax.swing.JLabel frog3;
    private javax.swing.JButton jButton1;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration                   
}

，我只知道Thread.sleep

嗯，这是行不通的，因为代码正在执行Event Dispatch Thread (EDT)这是重绘 GUI 的线程。因此，如果你一直告诉它睡觉，就永远没有机会重新粉刷自己。

所以如果你想使用Thread.sleep，你需要启动一个单独的Thread。

阅读 Swing 教程中的部分并发性 http://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html了解更多信息。也许您还可以使用 SwingWorker，如工作线程教程中讨论的那样。