drawlinetest.java

java练习程序

//用鼠标自由作画
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class drawLineTest extends Applet implements MouseMotionListener
{
	int x=-1, y=-1;
	public void init()
	{
		setBackground(Color.green);
		addMouseMotionListener(this);
	}
	
	public void paint(Graphics g)
	{
		if(x!=-1&&y!=-1)
		{
			g.setColor(Color.red);
			g.drawLine(x, y, x, y);
		}
	}
	
	public void mouseDragged(MouseEvent e)
	{
		x=(int)e.getX();
		y=(int)e.getY();
		repaint();
	}
	
	public void mouseMoved(MouseEvent e)
	{}
	
	public void update(Graphics g)
	{
		paint(g);
	}
}