scrollbar.java

一个关于java的滚动条程序

import java.awt.*;//*
import java.awt.event.*;
import java.applet.*;

public class scrollbar extends Applet implements AdjustmentListener  
{
	Scrollbar sb=new Scrollbar(Scrollbar.HORIZONTAL,10,10,0,160);
	int a;
	TextField tf; 
	Label l; 
	//boolean flag=false;
	public void init()
	{
		sb.addAdjustmentListener(this);
		tf = new TextField("0", 5); 
		tf.setEditable(false); 
		l = new Label("圆的直径为："); 
		add(l);
		add(sb);
	    add(tf);
	}
	public void adjustmentValueChanged(AdjustmentEvent e)
	{
		   
		if(e.getAdjustable()==sb)
		{
		   a=sb.getValue();
		   tf.setText(Integer.toString((sb.getValue()))); 
        }	 
		repaint();
	}
	public void paint(Graphics g)
	{
		g.drawOval(55,30,a,a);
	}
}