Swing ContainerListener介面

ContainerListener介面用於接收容器事件，處理容器事件的類需要實現此介面。

介面宣告

以下是java.awt.event.ContainerListener介面的宣告 -

public interface ContainerListener
extends EventListener

介面方法

方法繼承

該類從以下介面繼承方法 -

• java.awt.event.EventListener

ContainerListener範例

使用編輯器建立以下Java程式：ContainerListenerDemo.java

package com.yiibai.swing.listener;

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

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

    public ContainerListenerDemo() {
        prepareGUI();
    }

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

    private void prepareGUI() {
        mainFrame = new JFrame("Java SWING ContainerListener範例(tw511.com)");
        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 showContainerListenerDemo() {
        headerLabel.setText("Listener in action: ContainerListener");

        JPanel panel = new JPanel();
        panel.setBackground(Color.blue);
        panel.addContainerListener(new CustomContainerListener());

        JLabel msglabel = new JLabel("歡迎您來到易百網Swing教學.", JLabel.CENTER);
        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. ");
        }
    }
}

執行上面範例程式碼，得到以下結果：