比如，有的java源程序生成一个字节码文件，带有内部类的生成两个。可是有一种情况怎么回事呢？importjava.awt.*;importjavax.swing.*;importjava.awt.event.*;publicclassCardLayoutF...

比如，有的java源程序生成一个字节码文件，带有内部类的生成两个。可是有一种情况怎么回事呢？

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

public class CardLayoutFrame extends JFrame{

JButton btPrevious = new JButton("前一张");

JButton btNext = new JButton("下一张");

JPanel flowPanel = new JPanel(new FlowLayout());

JPanel cardPanel = new JPanel(new CardLayout());

int currentIndex = 0;

public CardLayoutFrame(){

this.getContentPane().add(flowPanel,BorderLayout.SOUTH);

this.getContentPane().add(cardPanel,BorderLayout.CENTER); cardPanel.add(getCard(1),"Card1");

cardPanel.add(getCard(2),"Card2");

flowPanel.add(btPrevious);

flowPanel.add(btNext);

ActionListener listener = new ActionListener(){

public void actionPerformed(ActionEvent e){

switchCard();

}

}; //为什么加一个";"号呢？

btPrevious.addActionListener(listener);

btNext.addActionListener(listener);

this.setSize(300,200);

this.setTitle("GardLayoutDemo");

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.show();

}

JPanel getCard(int index){

JPanel panel = new JPanel(new BorderLayout());

JLabel label = new JLabel("

"+"这是第"+index+"张卡片"+ "

label.setHorizontalAlignment(JLabel.CENTER);

panel.add(label);

return panel;

}

void switchCard(){

CardLayout cl = (CardLayout)cardPanel.getLayout();

if(currentIndex==0){

currentIndex++;

cl.show(cardPanel,"Card2");

}

else{

currentIndex--;

cl.show(cardPanel,"Card1");}}

public static void main(String[] args){

CardLayoutFrame frame = new CardLayoutFrame();

}

}

生成CardLayoutFrame$1.class还有CardLayoutFrame.class两个文件。

展开