那下面这段程序那???他的内部类引用了外部类的方法!!!
这该怎么办???import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;public class Sketch
{
public static void main(String[] args)
{
SketchFrame frame = new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}/**
A frame with a panel for sketching a figure
*/
class SketchFrame extends JFrame
{
public SketchFrame()
{
setTitle("Sketch");
setSize(WIDTH, HEIGHT); // add panel to frame SketchPanel panel = new SketchPanel();
Container contentPane = getContentPane();
contentPane.add(panel);
} public static final int WIDTH = 300;
public static final int HEIGHT = 200;
}/**
A panel for sketching with the keyboard.
*/
class SketchPanel extends JPanel
{
public SketchPanel()
{
last = new Point2D.Double(100, 100);
lines = new ArrayList();
KeyHandler listener = new KeyHandler();
addKeyListener(listener);
} public boolean isFocusTraversable()
{
return true; // allow panel to get input focus
} /**
Add a new line segment to the sketch.
@param dx the movement in x direction
@param dy the movement in y direction
*/
public void add(int dx, int dy)
{
// compute new end point
Point2D end = new Point2D.Double(last.getX() + dx,
last.getY() + dy); // add line segment
Line2D line = new Line2D.Double(last, end);
lines.add(line);
repaint(); // remember new end point
last = end;
} public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g; // draw all lines
for (int i = 0; i < lines.size(); i++)
g2.draw((Line2D)lines.get(i));
} private Point2D last;
private ArrayList lines; private static final int SMALL_INCREMENT = 1;
private static final int LARGE_INCREMENT = 5; private class KeyHandler implements KeyListener
{
public void keyPressed(KeyEvent event)
{
int keyCode = event.getKeyCode(); // set distance
int d;
if (event.isShiftDown())
d = LARGE_INCREMENT;
else
d = SMALL_INCREMENT; // add line segment
if (keyCode == KeyEvent.VK_LEFT) add(-d, 0);
else if (keyCode == KeyEvent.VK_RIGHT) add(d, 0);
else if (keyCode == KeyEvent.VK_UP) add(0, -d);
else if (keyCode == KeyEvent.VK_DOWN) add(0, d);
} public void keyReleased(KeyEvent event) {} public void keyTyped(KeyEvent event)
{
char keyChar = event.getKeyChar(); // set distance
int d;
if (Character.isUpperCase(keyChar))
{
d = LARGE_INCREMENT;
keyChar = Character.toLowerCase(keyChar);
}
else
d = SMALL_INCREMENT; // add line segment
if (keyChar == 'h') add(-d, 0);
else if (keyChar == 'l') add(d, 0);
else if (keyChar == 'k') add(0, -d);
else if (keyChar == 'j') add(0, d);
}
}
}
这该怎么办???import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;public class Sketch
{
public static void main(String[] args)
{
SketchFrame frame = new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}/**
A frame with a panel for sketching a figure
*/
class SketchFrame extends JFrame
{
public SketchFrame()
{
setTitle("Sketch");
setSize(WIDTH, HEIGHT); // add panel to frame SketchPanel panel = new SketchPanel();
Container contentPane = getContentPane();
contentPane.add(panel);
} public static final int WIDTH = 300;
public static final int HEIGHT = 200;
}/**
A panel for sketching with the keyboard.
*/
class SketchPanel extends JPanel
{
public SketchPanel()
{
last = new Point2D.Double(100, 100);
lines = new ArrayList();
KeyHandler listener = new KeyHandler();
addKeyListener(listener);
} public boolean isFocusTraversable()
{
return true; // allow panel to get input focus
} /**
Add a new line segment to the sketch.
@param dx the movement in x direction
@param dy the movement in y direction
*/
public void add(int dx, int dy)
{
// compute new end point
Point2D end = new Point2D.Double(last.getX() + dx,
last.getY() + dy); // add line segment
Line2D line = new Line2D.Double(last, end);
lines.add(line);
repaint(); // remember new end point
last = end;
} public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g; // draw all lines
for (int i = 0; i < lines.size(); i++)
g2.draw((Line2D)lines.get(i));
} private Point2D last;
private ArrayList lines; private static final int SMALL_INCREMENT = 1;
private static final int LARGE_INCREMENT = 5; private class KeyHandler implements KeyListener
{
public void keyPressed(KeyEvent event)
{
int keyCode = event.getKeyCode(); // set distance
int d;
if (event.isShiftDown())
d = LARGE_INCREMENT;
else
d = SMALL_INCREMENT; // add line segment
if (keyCode == KeyEvent.VK_LEFT) add(-d, 0);
else if (keyCode == KeyEvent.VK_RIGHT) add(d, 0);
else if (keyCode == KeyEvent.VK_UP) add(0, -d);
else if (keyCode == KeyEvent.VK_DOWN) add(0, d);
} public void keyReleased(KeyEvent event) {} public void keyTyped(KeyEvent event)
{
char keyChar = event.getKeyChar(); // set distance
int d;
if (Character.isUpperCase(keyChar))
{
d = LARGE_INCREMENT;
keyChar = Character.toLowerCase(keyChar);
}
else
d = SMALL_INCREMENT; // add line segment
if (keyChar == 'h') add(-d, 0);
else if (keyChar == 'l') add(d, 0);
else if (keyChar == 'k') add(0, -d);
else if (keyChar == 'j') add(0, d);
}
}
}
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