问题
I have an application that has a main GUI with a menubar, and another fullscreen frame, which makes some parts of the main GUI appear in fullscreen exclusive mode. When I am in fullscreen mode, I would like to bind a drop-down menu from the menu bar as jpopupmenu.
Swing provides the function getPopupMenu() in JMenu. This function seems to work fine at first glance. I can hover over the menuitems and move to and view the submenus. Hovering over the submenus does emphasize the submenus, hovering over a plain menuitem (or radiobuttonmenuitem or checkboxmenuitem) does not emphasize the item. However, I can't actually click on a menuitem. The keyboard-shortcuts do actually work fine, though. The problem is essentially the same as presented on this forum (where the problem is not solved, though):
http://www.java-forums.org/new-java/16463-jmenu-jpopupmenu.html
If I add a JMenuItem after the menubar has been initialized and used/shown in the main GUI (thus when switching to the fullscreen frame), the menu-item is actually clickable. This menu-item is in turn also clickable in the menubar of the main GUI. Executing getPopupMenu() directly after initializing the jMenu does not change anything. Not using the fullscreen exclusive-mode does also not change anything about the problem.
Edit
It seems I left out some important information: I'm testing the app on Mac OSX and using:
System.setProperty("apple.laf.useScreenMenuBar", "true");
To make the menu bar use the native menubar. If I disable this, the popup-menu works as expected. This seems like a bug in the mac java API? Is their some way to overcome, this?
I apologize for forgetting mentioning this, I wasn't aware this would influence anything (though it seems kind of obvious).
回答1:
Okay, I'm probably missing something, but I hacked this together really quickly and have no issues
public class PopupFrame extends javax.swing.JFrame {
/**
* Creates new form PopupFrame
*/
public PopupFrame() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jMenuBar1 = new javax.swing.JMenuBar();
mnuFile = new javax.swing.JMenu();
jMenuItem1 = new javax.swing.JMenuItem();
jMenuItem2 = new javax.swing.JMenuItem();
jMenuItem3 = new javax.swing.JMenuItem();
jMenuItem4 = new javax.swing.JMenuItem();
jMenuItem5 = new javax.swing.JMenuItem();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
addMouseListener(new java.awt.event.MouseAdapter() {
public void mousePressed(java.awt.event.MouseEvent evt) {
doMouseClicked(evt);
}
public void mouseReleased(java.awt.event.MouseEvent evt) {
doMouseClicked(evt);
}
public void mouseClicked(java.awt.event.MouseEvent evt) {
doMouseClicked(evt);
}
});
mnuFile.setText("File");
jMenuItem1.setText("New");
jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
doActionPerformed(evt);
}
});
mnuFile.add(jMenuItem1);
jMenuItem2.setText("Open");
jMenuItem2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
doActionPerformed(evt);
}
});
mnuFile.add(jMenuItem2);
jMenuItem3.setText("Save");
jMenuItem3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
doActionPerformed(evt);
}
});
mnuFile.add(jMenuItem3);
jMenuItem4.setText("Close");
jMenuItem4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
doActionPerformed(evt);
}
});
mnuFile.add(jMenuItem4);
jMenuItem5.setText("Exit");
jMenuItem5.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
doActionPerformed(evt);
}
});
mnuFile.add(jMenuItem5);
jMenuBar1.add(mnuFile);
setJMenuBar(jMenuBar1);
org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
.add(0, 278, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void doActionPerformed(java.awt.event.ActionEvent evt) {
JMenuItem mi = (JMenuItem) evt.getSource();
JOptionPane.showMessageDialog(this, "Clicked " + mi.getText());
}
private void doMouseClicked(java.awt.event.MouseEvent evt) {
if (evt.isPopupTrigger()) {
JPopupMenu popupMenu = mnuFile.getPopupMenu();
popupMenu.show(this, evt.getX(), evt.getY());
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(PopupFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(PopupFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(PopupFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(PopupFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new PopupFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem1;
private javax.swing.JMenuItem jMenuItem2;
private javax.swing.JMenuItem jMenuItem3;
private javax.swing.JMenuItem jMenuItem4;
private javax.swing.JMenuItem jMenuItem5;
private javax.swing.JMenu mnuFile;
// End of variables declaration
}
I apologies, I had to put it together while my 3 month old had a nap, so it's quick and ugly :P
UPDATE
After some playing around, it would seem that when we invoke the popup ourselves, I was changing the popup's parent reference (invoker) which meant that when the JMenu tried to show the popup, the context was all wrong.
I updated the doActionPerformed method to look like this:
JOptionPane.showMessageDialog(this, "Clicked " + mi.getText());
JPopupMenu popupMenu = mnuFile.getPopupMenu();
popupMenu.setInvoker(mnuFile);
Basically, resting the popup's client reference.
来源：https://stackoverflow.com/questions/11696833/java-swing-mac-osx-converting-jmenu-to-jpopupmenu-using-screenmenubar