aframe.java

主要是练习java中的按钮事件．通过对JButton 的注册来实现

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class aframe extends JFrame 
{
	JButton jb1;
	JButton jb2;
    Choice jc1;
	JTextField jt1;
	
	public aframe()
	{
		jb1=new JButton("show text");
		jb2=new JButton("text chang of choice");
		jc1=new Choice();
		jt1=new JTextField(12);
		getContentPane().setLayout(new GridLayout(2,2));
		jc1.addItem("red");
		jc1.addItem("yellow");
		jc1.addItem("green");
		getContentPane().add(jt1);
		getContentPane().add(jb1);
		getContentPane().add(jc1);
		getContentPane().add(jb2);
	
		Buttonlistener btl=new Buttonlistener();
		Choicelistener ch=new Choicelistener();
		
		jb1.addActionListener(btl);
		jc1.addItemListener(ch);
		
		
	}
	public static void main (String[] args)
    {
    	aframe af=new aframe();
    	af.setVisible(true);
    	af.setSize(300,200);
    	af.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    		
  class Buttonlistener implements ActionListener
    {
       	public void actionPerformed(ActionEvent e)
    	{
    		if(e.getSource()==jb1)
    		{
    			jt1.setText("ni hao");
    			
    		}
    	}
    }
    class Choicelistener implements ItemListener
    {
       public void itemStateChanged(ItemEvent e)
    	{
         	 	if(jc1.getSelectedItem()=="red")
         	 	{	jb2.setText("red");
    			    jb2.setBackground(Color.red);
    	        }
    			else if(jc1.getSelectedItem()=="green")
    				jb2.setText("green");
    				else if(jc1.getSelectedItem()=="yellow")
    					jb2.setText("yellow");
    					else 
    						jb2.setText("hello");
    					
    				
    				
    	}
    		
    }
    	
}