我正在尝试使用 ActionListener 退出菜单，但是我的代码无法正常工作，并且“退出程序”按钮没有执行任何操作。下面是代码：
import java.awt.*;
import java.awt.event.*;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.ButtonGroup;
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.JFrame;
public class testCoinSorterGUI extends testCoinSorter{
JTextArea output;
JScrollPane scrollPane;
public JMenuBar createMenuBar() {
JMenuBar menuBar;
JMenu menu, submenu;
JMenuItem menuItem;
JRadioButtonMenuItem rbMenuItem;
JCheckBoxMenuItem cbMenuItem;
//Create the menu bar.
menuBar = new JMenuBar();
//Build the first menu.
menu = new JMenu("Calculator");
menu.setMnemonic(KeyEvent.VK_A);
menu.getAccessibleContext().setAccessibleDescription(
"The only menu in this program that has menu items");
menuBar.add(menu);
menuItem = new JMenuItem("Coin calculator");
menu.add(menuItem);
menuItem = new JMenuItem("Multi Coin calculator");
menu.add(menuItem);
//Build second menu in the menu bar.
menu = new JMenu("Print coin list");
menu.setMnemonic(KeyEvent.VK_N);
menu.getAccessibleContext().setAccessibleDescription("This menu does nothing");
menuBar.add(menu);
//Build third menu in the menu bar.
menu = new JMenu("Set details");
menuBar.add(menu);
menuItem = new JMenuItem("Set currency");
menu.add(menuItem);
menuItem = new JMenuItem("Set minimum coin input value");
menu.add(menuItem);
menuItem = new JMenuItem("Set maximum coin input value");
menu.add(menuItem);
menu.addSeparator();
menuItem = new JMenuItem("Display program configurations");
menu.add(menuItem);
//Build fifth menu in the menu bar.
menu = new JMenu("Quit the program");
menuBar.add(menu);
menu.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
);
return menuBar;
}
public Container createContentPane() {
//Create the content-pane-to-be.
JPanel contentPane = new JPanel(new BorderLayout());
contentPane.setOpaque(true);
//Create a scrolled text area.
output = new JTextArea(5, 30);
output.setEditable(false);
scrollPane = new JScrollPane(output);
//Add the text area to the content pane.
contentPane.add(scrollPane, BorderLayout.CENTER);
return contentPane;
}
/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String path) {
java.net.URL imgURL = testCoinSorterGUI.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL);
} else {
System.err.println("Couldn't find file: " + path);
return null;
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("*** CoinSorterGUI ***");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
testCoinSorterGUI demo = new testCoinSorterGUI();
frame.setJMenuBar(demo.createMenuBar());
frame.setContentPane(demo.createContentPane());
//Display the window.
frame.setSize(680, 480);
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
目前我只想测试“退出程序”按钮，所以请忽略所有其他菜单。任何帮助将不胜感激，尽管我认为我已将代码按正确的顺序排列，但我真的很困惑。