基本概念围绕着这种“增量”或“变化”价值的观念。
然后，通过
将该状态值递增或递减，将其应用于您要更改的状态。
由于Swing的性质，您不能阻止“事件调度线程”，
否则最终将阻止处理传入事件（例如绘画
和按键事件）。
同样，
除了EDT之外，您永远不要尝试从任何线程更新任何UI组件（或可能影响UI的状态变量）。
尽管有一些技巧可以满足这些要求，但
最简单的方法是使用javax.swing.Timer，它会actionPerformed
在EDT中定期触发事件。
发生这种情况时，您可以按规定的数量“更新”所有元素并
重新粉刷屏幕。
import java.awt.BorderLayout;import java.awt.Dimension;import java.awt.EventQueue;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.KeyEvent;import java.awt.geom.AffineTransform;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;import javax.swing.AbstractAction;import javax.swing.ActionMap;import javax.swing.InputMap;import javax.swing.Jframe;import javax.swing.JPanel;import javax.swing.KeyStroke;import javax.swing.Timer;import javax.swing.UIManager;import javax.swing.UnsupportedLookAndFeelException;public class PacManTest { public static void main(String[] args) { new PacManTest(); } public PacManTest() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } Jframe frame = new Jframe("Test"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new MazePane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class PacMan { private int x; private int y; private int deltaX; private int deltaY; private BufferedImage sprite; public PacMan() { try { sprite = ImageIO.read(new File("PacMan.png")); } catch (IOException ex) { ex.printStackTrace(); } } public void move(int x, int y) { deltaX = x; deltaY = y; } public void update(MazePane pane) { x += deltaX; y += deltaY; if (x + sprite.getWidth() > pane.getWidth()) { x = pane.getWidth() - sprite.getWidth(); } else if (x < 0) { x = 0; } if (y + sprite.getHeight() > pane.getHeight()) { y = pane.getHeight() - sprite.getHeight(); } else if (y < 0) { y = 0; } } public void paint(MazePane pane, Graphics2D g2d) { Graphics2D g = (Graphics2D) g2d.create(); float angle = 0; if (deltaX != 0) { angle = deltaX > 0 ? 0 : 180; } else if (deltaY != 0) { angle = deltaY > 0 ? 90 : 270; } AffineTransform t = new AffineTransform(); t.translate(x, y); t.rotate(Math.toRadians(angle), sprite.getWidth() / 2, sprite.getHeight() / 2); g.setTransform(t); g.drawImage(sprite, 0, 0, pane); g.dispose(); } } public class MazePane extends JPanel { private PacMan pacMan; public MazePane() { pacMan = new PacMan(); Timer timer = new Timer(40, new ActionListener() { @Override public void actionPerformed(ActionEvent e) { pacMan.update(MazePane.this); repaint(); } }); timer.start(); InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW); ActionMap am = getActionMap(); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "left"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), "right"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "up"); im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), "down"); am.put("left", new MoveAction(pacMan, -4, 0)); am.put("right", new MoveAction(pacMan, 4, 0)); am.put("up", new MoveAction(pacMan, 0, -4)); am.put("down", new MoveAction(pacMan, 0, 4)); } @Override public Dimension getPreferredSize() { return new Dimension(200, 200); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D) g.create(); pacMan.paint(this, g2d); g2d.dispose(); } public class MoveAction extends AbstractAction { private int deltaX; private int deltaY; private PacMan pacMan; public MoveAction(PacMan pacMan, int deltaX, int deltaY) { this.deltaX = deltaX; this.deltaY = deltaY; this.pacMan = pacMan; } @Override public void actionPerformed(ActionEvent e) { pacMan.move(deltaX, deltaY); } } }}我还建议您花一些时间来学习“键绑 定”，KeyListener因为它存在焦点问题，这些键绑定能够
解决…
