import javax.swing.*;import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;public class Sketch
{
public static void main(String[] args) {
SketchFrame frame=new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show() ;
} } class SketchFrame extends JFrame
{
public SketchFrame()
{
setTitle("PlafTest");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
SketchPanel panel=new SketchPanel();
Container contentPane=getContentPane();
contentPane.add(panel); } public static final int DEFAULT_WIDTH=300;
public static final int DEFAULT_HEIGHT =200;
} class SketchPanel extends JPanel
{
public SketchPanel()
{
last = new Point2D.Double(100, 100);
lines = new ArrayList();
KeyHandler listener = new KeyHandler();
addKeyListener(listener);
setFocusable(true);
}
public void add(int dx,int dy)
{
Point2D end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D line=new Line2D.Double(last,end);
lines.add(line);
repaint();
last=end;
} public void paintrComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g; for(int i=0;i<lines.size();i++)
g2.draw((Line2D)lines.get(i)); } private Point2D last;
private ArrayList lines; private static final int SAMLL_INCREMENT=1;
private static final int LARGE_INCREMENT=5; private class KeyHandler implements KeyListener
{
public void KeyPressed(KeyEvent event)
{
int keyCode=event.getKeyCode();
int d;
if(event.isShiftDown())
d=LARGE_INCREMENT;
else
d=SAMLL_INCREMENT; 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);
}
//怎样实现
public void keyReleased(KeyEvent event)
{}
public void keyTyped(KeyEvent event)
{
char keyChar=event.getKeyChar();
int d;
if(Character.isUpperCase(keyChar))
{
d=LARGE_INCREMENT;
keyChar=Character.toLowerCase(keyChar);
}
else
d= SAMLL_INCREMENT; 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); }
} }
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;public class Sketch
{
public static void main(String[] args) {
SketchFrame frame=new SketchFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show() ;
} } class SketchFrame extends JFrame
{
public SketchFrame()
{
setTitle("PlafTest");
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
SketchPanel panel=new SketchPanel();
Container contentPane=getContentPane();
contentPane.add(panel); } public static final int DEFAULT_WIDTH=300;
public static final int DEFAULT_HEIGHT =200;
} class SketchPanel extends JPanel
{
public SketchPanel()
{
last = new Point2D.Double(100, 100);
lines = new ArrayList();
KeyHandler listener = new KeyHandler();
addKeyListener(listener);
setFocusable(true);
}
public void add(int dx,int dy)
{
Point2D end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
Line2D line=new Line2D.Double(last,end);
lines.add(line);
repaint();
last=end;
} public void paintrComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g; for(int i=0;i<lines.size();i++)
g2.draw((Line2D)lines.get(i)); } private Point2D last;
private ArrayList lines; private static final int SAMLL_INCREMENT=1;
private static final int LARGE_INCREMENT=5; private class KeyHandler implements KeyListener
{
public void KeyPressed(KeyEvent event)
{
int keyCode=event.getKeyCode();
int d;
if(event.isShiftDown())
d=LARGE_INCREMENT;
else
d=SAMLL_INCREMENT; 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);
}
//怎样实现
public void keyReleased(KeyEvent event)
{}
public void keyTyped(KeyEvent event)
{
char keyChar=event.getKeyChar();
int d;
if(Character.isUpperCase(keyChar))
{
d=LARGE_INCREMENT;
keyChar=Character.toLowerCase(keyChar);
}
else
d= SAMLL_INCREMENT; 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); }
} }
keyReleased是键盘放开时的事件,你要按键放开时有什么动作就实现它不就可以了么?