AWT » AWT PopupMenu類

AWT PopupMenu類

彈出選單表示可以在一個元件內的指定位置動態彈出的選單。

類的宣告

以下是java.awt.PopupMenu描述類的宣告：

public class CheckboxMenuItem
   extends MenuItem
      implements ItemSelectable, Accessible

類別建構函式

S.N. 建構函式與說明
1 PopupMenu() 
Creates a new popup menu with an empty name.
2 PopupMenu(String label) 
Creates a new popup menu with the specified name.

類方法

S.N. 方法和說明
1 void addNotify() 
Creates the popup menu's peer.
2 AccessibleContext getAccessibleContext() 
Gets the AccessibleContext associated with this PopupMenu.
3 MenuContainer getParent() 
Returns the parent container for this menu component.
4 void show(Component origin, int x, int y) 
Shows the popup menu at the x, y position relative to an origin component.

繼承的方法

這個類繼承的方法從以下類：

  • java.awt.MenuItem

  • java.awt.MenuComponent

  • java.lang.Object

PopupMenu 範例

選擇使用任何編輯器建立以下java程式 D:/ > AWT > com > yiibai > gui >

AWTMenuDemo 
package com.yiibai.gui;

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

public class AWTMenuDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AWTMenuDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AWTMenuDemo  awtMenuDemo = new AWTMenuDemo();     
      awtMenuDemo.showPopupMenuDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showPopupMenuDemo(){
      final PopupMenu editMenu = new PopupMenu("Edit"); 

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

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

      MenuItem pasteMenuItem = new MenuItem("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);   
      
      controlPanel.addMouseListener(new MouseAdapter() {
         public void mouseClicked(MouseEvent e) {            
               editMenu.show(controlPanel, e.getX(), e.getY());
         }               
      });
      controlPanel.add(editMenu); 

      mainFrame.setVisible(true);
   }
	
   class MenuItemListener implements ActionListener {
      public void actionPerformed(ActionEvent e) {            
         statusLabel.setText(e.getActionCommand() 
            + " MenuItem clicked.");
      }    
   }
}

編譯程式，使用命令提示字元。進入到D:/> AWT，然後鍵入以下命令。

D:AWT>javac comyiibaiguiAWTMenuDemo.java

如果沒有錯誤出現，這意味著編譯成功。使用下面的命令來執行程式。

D:AWT>java com.yiibai.gui.AWTMenuDemo

驗證下面的輸出。（點選螢幕中間。）

AWT PopupMenu