Swing 示例 - 建立彈出選單

以下示例展示瞭如何在 Java Swing 應用程式中顯示彈出選單。

我們使用以下 API。

• JPopupMenu − 建立彈出選單。

• JMenuItem − 建立選單項。

示例

import java.awt.*;
import java.awt.event.*;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;

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("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.");
      }    
   }   
}

使用命令提示符編譯程式。轉到 D:/ > SWING 並鍵入以下命令。

D:\SWING>javac com\tutorialspoint\gui\SwingMenuDemo.java

如果未發生錯誤，則表示編譯成功。使用以下命令執行該程式。

D:\SWING>java com.tutorialspoint.gui.SwingMenuDemo

驗證以下輸出。（單擊螢幕中間。）