大家好！我想用KeyListeners做一些事情，只要按下按钮，就会导致画布重新绘制。但是，问题是由于封装，KeyListener无法访问其他类中的任何方法。解决这个问题的关键是什么？
谢谢！
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.io.*;
public class FaceFrame extends JFrame {
private FaceCanvas face;
public FaceFrame() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(800, 800);
setVisible(true);
setLayout(new BorderLayout());
KeyListenerTester bob = new KeyListenerTester();
face = new FaceCanvas();
face.addKeyListener(bob);
add(face, BorderLayout.CENTER);
}
public static void main(String args[]) {
JFrame faceFrame = new FaceFrame();
}
}
class FaceCanvas extends Canvas {
private Face whiteGuy;
private Face redGuy;
public FaceCanvas() {
setBackground( Color.BLUE);
setSize( 800, 800 );
whiteGuy = new Face(50, 50, 150, 150, Color.WHITE, "White");
redGuy = new Face(300, 300, 150, 150, Color.RED, "Red");
}
public void paint( Graphics g ) {
// override paint method by re-defining it
whiteGuy.paint(g);
redGuy.paint(g);
repaint();
}
}
class Face {
int xpos, ypos;
int width, height;
Color skinTone;
String tattoo;
Font f;
public Face(int xpos, int ypos, int width, int height, Color skinTone, String tattoo) {
this.xpos = xpos;
this.ypos = ypos;
this.width = width;
this.height = height;
this.skinTone = skinTone;
this.tattoo = tattoo;
f = new Font( "Times New Roman", Font.ITALIC| Font.BOLD, 24 );
}
public void paint(Graphics g) {
g.setColor( skinTone );
g.drawOval( xpos, ypos, width, height );
g.drawLine( xpos+ 10, ypos+ height-30, xpos+ width-30, ypos + height- 30 );
g.setFont(f);
g.drawString( tattoo, xpos + 60, ypos + 20 );
}
}
class KeyListenerTester extends JFrame implements KeyListener {
JLabel label;
public KeyListenerTester() {
}
@Override
public void keyTyped(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
}
}
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
}
}
@Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
}
}
}