JPopupMenu知道单击了哪个JMenuItem

Question

my question in very simple. I have a JPopupMenu that shown two JMenuItem . The only way I have found to know which item are clicked using

class MenuActionListener implements ActionListener {
  public void actionPerformed(ActionEvent e) {
    System.out.println("Selected: " + e.getActionCommand());    
  }
}

but the command e.getActionCommand() print the text inside the item. I would like get an index from 0 to n to known which item are clicked and not the text (that can be modified). Is it possible ?

Answer 1

You Could...

Place each JMenuItem in a Map , with the int value you want

Map<JMenuItem, Integer> menuMap = new HashMap<JMenuItem, Integer>(25);
//...
JMenuItem item1 = ...
menuMap.put(item, 0);
JMenuItem item2 = ...
menuMap.put(item, 1);

Then in the ActionListener , you would simply look it up based on the source of the event...

public void actionPerformed(ActionEvent e) {
    JMenuItem item = (JMenuItem)e.getSource();
    int index = menuMap.get(item);

You Could...

Use a List and determine the index of the JMenuItem within the list...

List<JMenuItem> menuList = new ArrayList<JMenuItem>(25);
//...
JMenuItem item1 = ...
menuList.add(item);
JMenuItem item2 = ...
menuList.add(item);

//...

public void actionPerformed(ActionEvent e) {
    JMenuItem item = (JMenuItem)e.getSource();
    int index = menuList.indexOf(item);

You Could...

Make use of the Action API

public class IndexedAction extends AbstractAction {
    private int index;
    public IndexedAction(int index, String name) {
        this.index = index;
        putValue(NAME, name);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        // Use the index some how...
    }
}

//...

JPopupMenu menu = new JPopupMenu();
menu.add(new IndexedAction(0, "Item 1"));
menu.add(new IndexedAction(1, "Item 2"));
menu.addSeparator();
menu.add(new IndexedAction(2, "Item 3"));
menu.add(new IndexedAction(3, "Item 4"));

You Could...

Set the actionCommand property of the items...

JPopupMenu pm = ...;
pm.add("Item 1").setActionCommand("0");
pm.add("Item 2").setActionCommand("1");
menu.addSeparator();
pm.add("Item 3").setActionCommand("2");
pm.add("Item 4").setActionCommand("3");

The problem with this is you're going to have to parse the actionCommand of the ActionEvent back to an int ...not a really sound proof solution...

You Could...

Set the clientProperty of each JMenuItem

JPopupMenu pm = ...;
pm.add("Item 1").putClientProperty("keyValue", 0);
pm.add("Item 2").putClientProperty("keyValue", 1);
menu.addSeparator();
pm.add("Item 3").putClientProperty("keyValue", 2);
pm.add("Item 4").putClientProperty("keyValue", 3);

But this gets messy...

public void actionPerformed(ActionEvent e) {
    JMenuItem item = (JMenuItem)e.getSource();
    Object value = item.getClientProperty("keyValue");
    if (value instanceof Integer) {
        int index = ((Integer)value).intValue();

There's probably other solutions, but without knowing why you want to do this, it makes it impossible to make an accurate suggestion...sorry

Answer 2

The code below shows how to get the index of selected JMenuItem :

      class MenuActionListener implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent e) {
                JMenuItem menuitem=(JMenuItem) e.getSource();
                JPopupMenu popupMenu =(JPopupMenu) menuitem.getParent();
                int index= popupMenu.getComponentIndex(menuitem);
                System.out.println("index:"+index);
            }
      }

Answer 3

Why can't we do:

menu.getSelectionModel().getSelectedIndex()

which returns an int ?