下面的程序哪里出错？为什么我移动W,A,S,D键的时候坦克的方向不改变呢？
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class Demo extends JFrame {
Mypanel mp = null;
public static void main(String[] args) {
Demo mtg = new Demo();
}
public Demo() {
mp = new Mypanel();
Thread t=new Thread(mp);
t.start();
this.add(mp);
this.addKeyListener(mp);
this.setSize(800,700);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
}
class Mypanel extends JPanel implements KeyListener ,Runnable{
int x=100;
int y=100;
int direct=0;
int speed=1;
int color;
public void paint(Graphics g){
super.paint(g);
g.setColor(Color.yellow);
g.fill3DRect(x+11,y+12,50,5,false);
g.fill3DRect(x+11,y+44,50,5,false);
g.setColor(Color.red);
g.fillRect(x+19,y+15,30,30);
g.setColor(Color.BLUE);
g.fillOval(x+23, y+18, 23,23);
g.setColor(Color.black);
g.drawLine(x+34,y+30,x+71,y+30);
}
public void move(){
Graphics g = null;
switch(direct){
case 0:
g.setColor(Color.yellow);
g.fill3DRect(x+17,y+5,5,50,false);
g.fill3DRect(x+48,y+5,5,50,false);
g.setColor(Color.red);
g.fillRect(x+19,y+15,30,30);
g.setColor(Color.BLUE);
g.fillOval(x+23, y+18, 23,23);
g.setColor(Color.green);
g.drawLine(x+34,y+34,x+34,y-3);
break;
case 1:
g.setColor(Color.yellow);
g.fill3DRect(x+11,y+12,50,5,false);
g.fill3DRect(x+11,y+44,50,5,false);
g.setColor(Color.red);
g.fillRect(x+19,y+15,30,30);
g.setColor(Color.BLUE);
g.fillOval(x+23, y+18, 23,23);
g.setColor(Color.green);
g.drawLine(x+34,y+30,x-4,y+30);
break;
case 2:
g.setColor(Color.yellow);
g.fill3DRect(x+17,y+5,5,50,false);
g.fill3DRect(x+48,y+5,5,50,false);
g.setColor(Color.red);
g.fillRect(x+19,y+15,30,30);
g.setColor(Color.BLUE);
g.fillOval(x+23, y+18, 23,23);
g.setColor(Color.green);
g.drawLine(x+34,y+34,x+34,y+71);
break;
case 3:
g.setColor(Color.yellow);
g.fill3DRect(x+11,y+12,50,5,false);
g.fill3DRect(x+11,y+44,50,5,false);
g.setColor(Color.red);
g.fillRect(x+19,y+15,30,30);
g.setColor(Color.BLUE);
g.fillOval(x+23, y+18, 23,23);
g.setColor(Color.green);
g.drawLine(x+34,y+30,x+71,y+30);
break;
}
}
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_W)
{
this.setdirect(0);
y-=4;
} else if (e.getKeyCode() == KeyEvent.VK_D)
{
this.setdirect(1);
x+=4;
} else if (e.getKeyCode() == KeyEvent.VK_S)
{
this.setdirect(2);
y+=4;
} else if (e.getKeyCode() == KeyEvent.VK_A)
{
this.setdirect(3);
x-=4;
}
this.repaint();
}
private void setdirect(int i) {
}
public void keyReleased(KeyEvent arg0) {
}
public void keyTyped(KeyEvent arg0) {
}
public void run() {
}
}
[解决办法]
帮你改了一下，调试过可以了，你对比一下有什么不同吧：
import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.util.*;public class Demo extends JFrame { Mypanel mp = null; public static void main(String[] args) { Demo mtg = new Demo(); } public Demo() { mp = new Mypanel(); Thread t=new Thread(mp); t.start(); this.add(mp); this.addKeyListener(mp); this.setSize(800,700); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setVisible(true); }}class Mypanel extends JPanel implements KeyListener ,Runnable{ int x=100; int y=100; int direct=0; int speed=1; int color; public void paint(Graphics g){super.paint(g);/*g.setColor(Color.yellow);g.fill3DRect(x+11,y+12,50,5,false);g.fill3DRect(x+11,y+44,50,5,false);g.setColor(Color.red);g.fillRect(x+19,y+15,30,30);g.setColor(Color.BLUE);g.fillOval(x+23, y+18, 23,23);g.setColor(Color.black);g.drawLine(x+34,y+30,x+71,y+30);*/move(g);} public void move(Graphics g){//Graphics g = null;switch(direct){case 0:g.setColor(Color.yellow);g.fill3DRect(x+17,y+5,5,50,false);g.fill3DRect(x+48,y+5,5,50,false);g.setColor(Color.red);g.fillRect(x+19,y+15,30,30);g.setColor(Color.BLUE);g.fillOval(x+23, y+18, 23,23);g.setColor(Color.green);g.drawLine(x+34,y+34,x+34,y-3);break;case 1:g.setColor(Color.yellow);g.fill3DRect(x+11,y+12,50,5,false);g.fill3DRect(x+11,y+44,50,5,false);g.setColor(Color.red);g.fillRect(x+19,y+15,30,30);g.setColor(Color.BLUE);g.fillOval(x+23, y+18, 23,23);g.setColor(Color.green);//g.drawLine(x+34,y+30,x-4,y+30);g.drawLine(x+34,y+30,x+71,y+30);break; case 2:g.setColor(Color.yellow);g.fill3DRect(x+17,y+5,5,50,false);g.fill3DRect(x+48,y+5,5,50,false);g.setColor(Color.red);g.fillRect(x+19,y+15,30,30);g.setColor(Color.BLUE);g.fillOval(x+23, y+18, 23,23);g.setColor(Color.green);g.drawLine(x+34,y+34,x+34,y+71);break;case 3:g.setColor(Color.yellow);g.fill3DRect(x+11,y+12,50,5,false);g.fill3DRect(x+11,y+44,50,5,false);g.setColor(Color.red);g.fillRect(x+19,y+15,30,30);g.setColor(Color.BLUE);g.fillOval(x+23, y+18, 23,23);g.setColor(Color.green);//g.drawLine(x+34,y+30,x+71,y+30);g.drawLine(x+34,y+30,x-4,y+30);break;} } public void keyPressed(KeyEvent e) { if (e.getKeyCode() == KeyEvent.VK_W) { this.setdirect(0);y-=4; } else if (e.getKeyCode() == KeyEvent.VK_D) { this.setdirect(1); x+=4; } else if (e.getKeyCode() == KeyEvent.VK_S) { this.setdirect(2);y+=4; } else if (e.getKeyCode() == KeyEvent.VK_A) { this.setdirect(3);x-=4; } this.repaint(); }private void setdirect(int i) { this.direct=i;}public void keyReleased(KeyEvent arg0) { } public void keyTyped(KeyEvent arg0) { }public void run() {}}