leftrightpanel.java

程序显示一个书签和两个按钮

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LeftRightPanel extends JPanel
{
	private JButton left,right;
	private JLabel label;
	private JPanel buttonPanel;
	public LeftRightPanel()
	{
		left=new JButton("Left");
		right=new JButton("Right");
		
		ButtonListener listener=new ButtonListener();
		left.addActionListener(listener);
		right.addActionListener(listener);
		
		label=new JLabel("Push a button");
		
		buttonPanel=new JPanel();
		buttonPanel.setPreferredSize(new Dimension(200,40));
		buttonPanel.setBackground(Color.blue);
		buttonPanel.add(left);
		buttonPanel.add(right);
		
		setPreferredSize(new Dimension(200,80));
		setBackground(Color.cyan);
		add(label);
		add(buttonPanel);
	}
	
	private class ButtonListener implements ActionListener
	{
		public void actionPerformed(ActionEvent event)
		{
			if (event.getSource()==left)
			    label.setText("left");
			else
			    label.setText("right");
		}
	}
}