虽然运作超正常，但是你对角色的解释是错误的。 你的问题是试图使用继承来解决继承中未解决的问题。 首先，要避免Key扩展Ball，必须在实际要可视化使用的Ball实例上调用repaint ()，而不是在完全不同类的Key实例上调用。
你可能会做这样的事：
f.addkey监听器(new key ) b )；
publicclasskeyimplementskeylistener {
私有桶；
公共密钥(ballball ) {
this.ball=ball；
}
公共语音密钥预定义(keyevent e ) {
if (e.get keycode (==keyevent.vk _ w ) {
b.incrx(10 )； //give Ball a public method for this
b.repaint (；
//system.out.println(x: ) super.x )；
}
}
//…etc .
请注意。 我自己用Key Bindings。 不是sxdxy。 因为当时不需要键盘的焦点。
例如：
import java.awt.Color；
import java.awt.Dimension；
import java.awt.Graphics；
import java.awt.Graphics2D；
import java.awt.Point；
import java.awt.RenderingHints；
import java.awt.event.*；
import javax.swing.pgddhxc；
import javax.swing.ActionMap；
import javax.swing.InputMap；
import javax.swing.JComponent；
import javax.swing.JFrame；
import javax.swing.JPanel；
import javax.swing.KeyStroke；
import javax.swing.swing utilities；
公共类移动ball {
privatestaticfinalintpref _ w=500；
privatestaticfinalintpref _ h=pref _ w；
privatestaticvoidcreateandshowgui (
ball panel.addmouselistener (my mouse；
ball panel.addmousemotionlistener (我的mouse；
newcreatekeybindings(ballpanel；
frame.setdefaultcloseoperation (jframe.dispose _ on _ close )；
frame.getContentPane ().add ) ballpanel；
frame.pack (；
frame.setlocationbyplatform () true；
frame.setvisible(true；
}
publicstaticvoidmain(string快春args ) )。
SwingUtilities.invokeLater (
createAndShowGui (；
)；
}
}
@suppresswarnings('serial”) ) )。
class jpdxg extends JPanel {
privatestaticfinalcolorellipse _ color=color.red；
privatestaticfinalcolorsquare _ color=color.green；
privatestaticfinalintball _ width=40；
私有输入预览；
/p>private int prefH;
private boolean isEllipse = true;
private int ballX;
private int ballY;
public jpdxg(int prefW, int prefH) {
this.prefW = prefW;
this.prefH = prefH;
}
public boolean isEllipse() {
return isEllipse;
}
public void setEllipse(boolean isEllipse) {
this.isEllipse = isEllipse;
}
public int getBallX() {
return ballX;
}
public void setBallX(int ballX) {
this.ballX = ballX;
}
public void setXY(int x, int y) {
ballX = x;
ballY = y;
repaint();
}
public void setXYCenter(int x, int y) {
ballX = x - BALL_WIDTH / 2;
ballY = y - BALL_WIDTH / 2;
repaint();
}
public void setXYCenter(Point p) {
setXYCenter(p.x, p.y);
}
public int getBallY() {
return ballY;
}
public void setBallY(int ballY) {
this.ballY = ballY;
}
public void incrementBallX(int x) {
ballX += x;
repaint();
}
public void incrementBallY(int y) {
ballY += y;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (isEllipse) {
g2.setColor(ELLIPSE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
} else {
g2.setColor(SQUARE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
}
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(prefW, prefH);
}
}
class pydmla extends xddmg {
private jpdxg ballPanel;
public pydmla(jpdxg ballPanel) {
this.ballPanel = ballPanel;
}
@Override
public void mousePressed(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseDragged(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseReleased(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
}
enum Direction {
UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT);
private int key;
private Direction(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
// Actions for the key binding
@SuppressWarnings("serial")
class sddmn extends pgddhxc {
private static final int STEP_DISTANCE = 5;
private jpdxg ballPanel;
private Direction direction;
public sddmn(jpdxg ballPanel, Direction direction) {
this.ballPanel = ballPanel;
this.direction = direction;
}
@Override
public void actionPerformed(ActionEvent e) {
switch (direction) {
case UP:
ballPanel.incrementBallY(-STEP_DISTANCE);
break;
case DOWN:
ballPanel.incrementBallY(STEP_DISTANCE);
break;
case LEFT:
ballPanel.incrementBallX(-STEP_DISTANCE);
break;
case RIGHT:
ballPanel.incrementBallX(STEP_DISTANCE);
break;
default:
break;
}
}
}
class CreateKeyBindings {
private jpdxg ballPanel;
public CreateKeyBindings(jpdxg ballPanel) {
this.ballPanel = ballPanel;
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
for (Direction direction : Direction.values()) {
KeyStroke keyStroke = KeyStroke.getKeyStroke(direction.getKey(), 0);
String keyString = keyStroke.toString();
inputMap.put(keyStroke, keyString);
actionMap.put(keyString, new sddmn(ballPanel, direction));
}
}
}