Java设计三个分别是rng的滑动条，改变背景颜色

package 的;
import java.awt.Color; 
import java.awt.Container; 
import java.awt.GridLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
  
import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JTextField; 
  
public class Test2 extends JFrame{ 
   
 public Test2(){ 
 Container c=getContentPane(); 
 c.setLayout(new GridLayout(4,2)); 
 JLabel j1=new JLabel("                    R:"); 
 JTextField jt1=new JTextField(); 
 c.add(j1); 
 c.add(jt1); 
 JLabel j2=new JLabel("                    G:"); 
 JTextField jt2=new JTextField(); 
 c.add(j2); 
 c.add(jt2); 
 JLabel j3=new JLabel("                    B:"); 
 JTextField jt3=new JTextField(); 
 c.add(j3); 
 c.add(jt3); 
 JButton jb=new JButton("确认");