使用卡片布局管理器不显示标签内容

label.setForeground(new Color(255,0,0,0));//此处多输入了一个0，导致窗口默认不显示，改为：new Color(255,0,0);//

package e24_02;

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

public class ExampleFrame_02 extends JFrame {
	
	private static final long serialVersionUID=1L;
	private JPanel cardPanel;
	private CardLayout cardLayout;
	
	public static void main(String args[]){
		ExampleFrame_02 frame=new ExampleFrame_02();
		frame.setVisible(true);
	}
	
	public ExampleFrame_02(){
		super();
		setTitle("使用卡片布局管理器");
		setBounds(100,100,600,400);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		cardLayout=new CardLayout();
		cardPanel=new JPanel(cardLayout);
		getContentPane().add(cardPanel, BorderLayout.CENTER);
		
		String[] labelNames= { "卡片A","卡片B","卡片C" };
	    for(int i=0;i