changecolor.java

本人在JAVA学习中的一点小实验

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class ChangeColor extends JFrame{
	JPanel p1,p2;
	JButton b1,b2,b3;
	Container cp =null;
	
	public ChangeColor(){
    	this("No Title");;
	}
	public ChangeColor(String title){
  	 super(title);
     p1 = new JPanel();
     p2 = new JPanel();
     p1.setLayout(new FlowLayout(FlowLayout.CENTER,20,10));
     p2.setLayout(new FlowLayout());
     
     b1 = new JButton("Red");
     b2 = new JButton("Green");
     b3 = new JButton("Blue");
     cp = getContentPane();
     
     p2.add(b1);p2.add(b2);p2.add(b3);
     cp.add(p1,BorderLayout.CENTER); 
     cp.add(p2, BorderLayout.SOUTH);
     AL listener =new AL();
     b1.addActionListener(listener);
     b2.addActionListener(listener);
     b3.addActionListener(listener);
     
   } 
  
  class AL implements ActionListener{
  	public void actionPerformed(ActionEvent e){
  		if((JButton)e.getSource()==b1)
  		     p1.setBackground(Color.RED);
  		if((JButton)e.getSource()==b2)
  		    p1.setBackground(Color.GREEN);
  		if((JButton)e.getSource()==b3)
  		   p1.setBackground(Color.BLUE);
  		
  	}
  }
  public static void main(String args[]){
  	 ChangeColor c=new ChangeColor("Change Color");
  	 c.setSize(400,240);
     c.setVisible(true); 
     c.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
  }
}