介绍

用于接收容器事件的接口ContainerListener。过程容器事件的类需要实现这个接口。

类的声明

以下声明是java.awt.event.ContainerListener接口：

public interface ContainerListener
extends EventListener

接口中的方法

S.N.	方法＆说明
1	void componentAdded(ContainerEvent e)  Invoked when a component has been added to the container.
2	void componentRemoved(ContainerEvent e)  Invoked when a component has been removed from the container.

继承的方法

这个类继承的方法从下面的接口：

• java.awt.event.EventListener

AdjustmentListener示例

选择使用任何编辑器创建以下java程序 D:/ > AWT > com > yiibai > gui >

AwtListenerDemo

package com.yiibai.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtListenerDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtListenerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtListenerDemo  awtListenerDemo = new AwtListenerDemo();  
      awtListenerDemo.showContainerListenerDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
   
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

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

   private void showContainerListenerDemo(){
      headerLabel.setText("Listener in action: ContainerListener");      

      ScrollPane panel = new ScrollPane();      
      panel.setBackground(Color.magenta);            
      panel.addContainerListener(new CustomContainerListener());  

      Label msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");
      panel.add(msglabel);
   
      controlPanel.add(panel);
      mainFrame.setVisible(true);  
   }

   class CustomContainerListener implements ContainerListener {
      public void componentAdded(ContainerEvent e) {
         statusLabel.setText(statusLabel.getText() 
         + e.getComponent().getClass().getSimpleName() + " added. ");
      }

      public void componentRemoved(ContainerEvent e) {
         statusLabel.setText(statusLabel.getText() 
         + e.getComponent().getClass().getSimpleName() + " removed. ");
      }
   }
}

编译程序，使用命令提示符。进入到D:/> AWT，然后键入以下命令。

D:AWT>javac comyiibaiguiAwtListenerDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

D:AWT>java com.yiibai.gui.AwtListenerDemo

验证下面的输出