怎样制作弹出菜单（pop-up menu)?

Question

我faint了，你用jb，不是和c++builder一样作么。

Answer 1

刚学编程，什么都不懂，没用过cbuilder，请多包涵
不过还是请回答，谢谢

Answer 2

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;public class PopupDemo extends JFrame
{
public PopupDemo()
{
Container contentPane = getContentPane();
final JLabel label = new JLabel("Click here");
label.setHorizontalAlignment(JLabel.CENTER);
final JPopupMenu popup = new JPopupMenu();

popup.add(new JMenuItem("item one"));
popup.add(new JMenuItem("item two"));
popup.add(new JMenuItem("item three"));
popup.add(new JMenuItem("item four"));
popup.add(new JMenuItem("item five"));

contentPane.add(label,BorderLayout.CENTER);

label.addMouseListener(new MouseAdapter()
{
public void mousePressed(MouseEvent e)
{
popup.show(label,e.getX(),e.getY());
}
});

setTitle("Popup Menu");
setSize(500,400);
}

public static void main(String[] args)
{
JFrame frame = new PopupDemo();
frame.setVisible(true);
}
}

Answer 3

我new了一个JPopupMenu,但是运行show()方法的时候,总是提示:parent is null,但我的show方法的parent参数不为空,是一个JInternalFrame类型的对象,弹出菜单总是显示不了,请问是怎么回事?

Answer 4

popMenu pm;
pm = new popMenu();
pm.show(itf, e.getX(), e.getY());poopMenu是一个继承自JPopupMenu的类,添加了两个菜单条
itf是一个JInternalFrame的类new的时候没问题
show的时候有问题

Answer 5

PopupMenu pm = new PopupMenu();
popup.show(e.getComponent(), e.getX(), e.getY());

Answer 6

改成e.getComponent()以后仍然不行,出错信息如下:
Exception occurred during event dispatching:java.lang.NullPointerException: parent is null void java.awt.PopupMenu.show(java.awt.Component, int, int) PopupMenu.java:107 void lj.interfaces.Face$DbClick.mousePressed(java.awt.event.MouseEvent) Face.java:513 void java.awt.AWTEventMulticaster.mousePressed(java.awt.event.MouseEvent) AWTEventMulticaster.java:221 void java.awt.Component.processMouseEvent(java.awt.event.MouseEvent) Component.java:3712 void java.awt.Component.processEvent(java.awt.AWTEvent) Component.java:3544 void java.awt.Container.processEvent(java.awt.AWTEvent) Container.java:1164 void java.awt.Component.dispatchEventImpl(java.awt.AWTEvent) Component.java:2593 void java.awt.Container.dispatchEventImpl(java.awt.AWTEvent) Container.java:1213 void java.awt.Component.dispatchEvent(java.awt.AWTEvent) Component.java:2497 void java.awt.LightweightDispatcher.retargetMouseEvent(java.awt.Component, int, java.awt.event.MouseEvent) Container.java:2451 boolean java.awt.LightweightDispatcher.processMouseEvent(java.awt.event.MouseEvent) Container.java:2210 boolean java.awt.LightweightDispatcher.dispatchEvent(java.awt.AWTEvent) Container.java:2125 void java.awt.Container.dispatchEventImpl(java.awt.AWTEvent) Container.java:1200 void java.awt.Component.dispatchEvent(java.awt.AWTEvent) Component.java:2497 void java.awt.EventQueue.dispatchEvent(java.awt.AWTEvent) EventQueue.java:339 boolean java.awt.EventDispatchThread.pumpOneEventForHierarchy(java.awt.Component) EventDispatchThread.java:131 void java.awt.EventDispatchThread.pumpEventsForHierarchy(java.awt.Conditional, java.awt.Component) EventDispatchThread.java:98 void java.awt.EventDispatchThread.pumpEvents(java.awt.Conditional) EventDispatchThread.java:93 void java.awt.EventDispatchThread.run() EventDispatchThread.java:85

Answer 7

JInternalFrame类好像是继承自component类啊

Answer 8

你用
    JPopupMenu pm = new JPopupMenu();
    pm.add(new JMenuItem("haha"));
    pm.show(e.getComponent(),e.getX(),e.getY());
 这个就没有问题了。

Answer 9

window open{"filename.jsp","title",toolbar=yes/no,left= ,top= , width= ,height= ,menubar=yes/no ,systemMenu=yes/no"}

Answer 10

window.open{"filename.jsp","title",toolbar=yes/no,left= ,top= , width= ,height= ,menubar=yes/no ,systemMenu=yes/no"}

Answer 11

唉，继承错了，应该JPopupMenu，我继承的是popupMenu,改一下就行了，呵呵，我真菜！