這是我編的壹個畫線的小程序，反正無論如何就是畫不出線啊，求哪位高手幫我看看啊~~~~~謝謝了~~~~~~~~~~

我給妳個：

import java.awt.Graphics;

import java.awt.event.*;

import javax.swing.*;

public class draw extends JFrame implements MouseMotionListener,MouseListener{

int startX=0;

int startY=0;

public static void main(String args[])

{

draw d=new draw();//初始化對象，調用構造方法

d.setVisible(true);

d.setBounds(0, 0, 300, 300);

}

public draw()

{

this.addMouseListener(this);

this.addMouseMotionListener(this);

}

public void mouseDragged(MouseEvent e) {

Graphics g=this.getGraphics();

g.drawLine(startX, startY, e.getX(), e.getY());

startX=e.getX();

startY=e.getY();

}

public void mousePressed(MouseEvent e) {

startX=e.getX();

startY=e.getY();

}

//後面這些用不到，但是因為是抽象的所以方法要全部實例化

public void mouseMoved(MouseEvent e) {}

public void mouseClicked(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

}