如何在Swing中创建弹出菜单项

说明

以下示例展示了如何在Swing中创建弹出菜单项。

我们正在使用以下 API。

• JPopupMenu ： 创建弹出菜单。

• JMenuItem ： 创建菜单项。

代码示例

package com.yiidian;

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

public class SwingJpopupMenu{
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel; 

   public SwingJpopupMenu(){
      prepareGUI();
   }
   public static void main(String[] args){
      SwingJpopupMenu  swingMenuDemo = new SwingJpopupMenu();     
      swingMenuDemo.showPopupMenuDemo();
   }
   private void prepareGUI(){
      mainFrame = new JFrame("一点教程网：Java SWING Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));

      headerLabel = new JLabel("",JLabel.CENTER );
      statusLabel = new JLabel("",JLabel.CENTER);        
      statusLabel.setSize(350,100);
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });
      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   private void showPopupMenuDemo(){
      final JPopupMenu editMenu = new JPopupMenu("Edit"); 

      JMenuItem cutMenuItem = new JMenuItem("Cut");
      cutMenuItem.setActionCommand("Cut");

      JMenuItem copyMenuItem = new JMenuItem("Copy");
      copyMenuItem.setActionCommand("Copy");

      JMenuItem pasteMenuItem = new JMenuItem("Paste");
      pasteMenuItem.setActionCommand("Paste");

      MenuItemListener menuItemListener = new MenuItemListener();

      cutMenuItem.addActionListener(menuItemListener);
      copyMenuItem.addActionListener(menuItemListener);
      pasteMenuItem.addActionListener(menuItemListener);

      editMenu.add(cutMenuItem);
      editMenu.add(copyMenuItem);
      editMenu.add(pasteMenuItem);   

      mainFrame.addMouseListener(new MouseAdapter() {
         public void mouseClicked(MouseEvent e) {
            editMenu.show(mainFrame, e.getX(), e.getY());
         }               
      });
      mainFrame.add(editMenu); 
      mainFrame.setVisible(true);
   }
   class MenuItemListener implements ActionListener {
      public void actionPerformed(ActionEvent e) {            
         statusLabel.setText(e.getActionCommand() + " MenuItem clicked.");
      }    
   }   
}

执行效果如下：