java - ComponentListener不起作用

请看下面的代码。

package normal;

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

public class MainForm extends JFrame implements ComponentListener
{
    private JTabbedPane tab;

    private InsertForm insertForm;
    private UpdateDeleteForm updateDelete;
    private SearchForm searchForm;

    public MainForm()
    {
        tab = new JTabbedPane();
        insertForm = new InsertForm();
        updateDelete = new UpdateDeleteForm();
        searchForm = new SearchForm();

        //Creating the main window
        tab.add(insertForm,"Insert");
        tab.add(updateDelete,"Update/Delete");
        tab.add(searchForm,"Search");
        tab.addChangeListener(new TabChangeWork());

        getContentPane().add(tab);




       // this.setSize(500,500);
        this.setTitle("My Phone Book App");
        this.setResizable(false);
        this.pack();
        this.validate();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

    @Override
    public void componentResized(ComponentEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void componentMoved(ComponentEvent e)
    {
        System.out.println("X Location: "+this.getX());
    }

    @Override
    public void componentShown(ComponentEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void componentHidden(ComponentEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    private class TabChangeWork implements ChangeListener
    {

        @Override
        public void stateChanged(ChangeEvent e)
        {
            JTabbedPane tabSource = (JTabbedPane)e.getSource();

            int index = tabSource.getSelectedIndex();
            System.out.println("Tab Changed to: "+tabSource.getTitleAt(index));


            if(tabSource.getTitleAt(index).equals("Update/Delete"))
            {
                updateDelete.addNames();
            }
        }

    }
}

在这里，ComponentListener无法正常工作，因为方法“ ComponentMoved”内部的操作未发生。我试图获取如果移动了JFrame的新坐标。为什么不起作用？请帮忙！！

最佳答案

您尚未在代码中的任何地方向ComponentListener注册...

像这样做....

component_to_monitor.addComponentListener(this);