此程序实现点击按钮,下面显示点击次数。编译时出错了,请问错在哪里?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class SwingApplication{
private static String labelPrefix="Number of button clicks";
private int numClicks=0;
public Component createComponents(){
final JLabel label=new JLabel(labelPrefix+"0  ");
JButton button=new JButton("I'm a String button");
button.setMnemonic(KeyEvent.VK_I);
button.addActionListener(new ActionAdapter(){   
public void actionPerformed(ActionEvent e)
{
numClicks++;
label.setText(labelPrefix+numClicks);
}
});
label.setLabelFor(button);
JPanel pane=new JPanel();
pane.setBorder(BorderFactory.createEmptyBorder(
30,
30,
10,
30)
);
pane.setLayout(new GridLayout(0,1));
pane.add(button);
pane.add(label);
return pane;
}
public static void main(String args[]){
try{
UIManager.setLookAndFeel(
UIManager.getCrossPlatformLookAndFeelClassName());
}catch(Exception e){}
JFrame frame=new JFrame("SwingApplication");
SwingApplication app=new SwingApplication();
Component contents=app.createComponents();
frame.getContentPane().add(contents,BorderLayout.CENTER);
frame.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
frame.pack();
frame.setVisible(true);
}
}