Swing ItemListener接口

ItemEvent類的對象應(yīng)該實現(xiàn)這個接口。處理類的一個組件必須注冊。使用addItemListener()方法，該對象可以被注冊。當動作事件發(fā)生時，調(diào)用該對象的itemStateChanged方法。

接口聲明

以下是聲明 java.awt.event.ItemListener接口：

public interface ItemListener
   extends EventListener

接口方法

方法繼承

這個接口從以下接口繼承的方法：

• java.awt.EventListener

ItemListener 例子

選擇使用任何編輯器創(chuàng)建以下java程序在 D:/ > SWING > com > yiibai > gui >

package com.yiibai.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SwingListenerDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;

   public SwingListenerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      SwingListenerDemo  swingListenerDemo = new SwingListenerDemo();  
      swingListenerDemo.showItemListenerDemo();
   }

   private void prepareGUI(){
      mainFrame = new JFrame("Java SWING Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));

      headerLabel = new JLabel("",JLabel.CENTER );
      statusLabel = new JLabel("",JLabel.CENTER);        

      statusLabel.setSize(350,100);
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
	        System.exit(0);
         }        
      });    
      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showItemListenerDemo(){
      headerLabel.setText("Listener in action: ItemListener");      
      JCheckBox chkApple = new JCheckBox("Apple");
      JCheckBox chkMango = new JCheckBox("Mango");
      JCheckBox chkPeer = new JCheckBox("Peer");
   
      chkApple.addItemListener(new CustomItemListener());
      chkMango.addItemListener(new CustomItemListener());
      chkPeer.addItemListener(new CustomItemListener());

      controlPanel.add(chkApple);
      controlPanel.add(chkMango);
      controlPanel.add(chkPeer);               
      mainFrame.setVisible(true); 
   }
     
     
   class CustomItemListener implements ItemListener {
      public void itemStateChanged(ItemEvent e) {
         statusLabel.setText(((JCheckBox)e.getItem()).getText()
         +" Checkbox: " 
         + (e.getStateChange()==上一篇：Swing AdjustmentListener接口下一篇：Swing JComponent類