I wanted to add a dynamic menu contribution item to the popup menu of project explorer. I could not immediately find out how to do this, so I decided to document it here. Eventually it turned out to be quite easy.

First you have to add the menu contribution to your plugin.xml. I wanted to add an extra menu item to the project explorer so I used "popup:org.eclipse.ui.navigator.ProjectExplorer#PopupMenu?after=additions" as locationURI. Next you only have to specify a class that will create the menu item and specify an id.

<extension point="org.eclipse.ui.menus">
  <menuContribution locationURI="popup:org.eclipse.ui.navigator.ProjectExplorer#PopupMenu?after=additions">
    <dynamic
              class="com.sigasi.MydynamicMenu"
              id="com.sigasi.myDynamicMenu">
    </dynamic>
  </menuContribution>
</extension>

Next you have to create the Java class that extends org.eclipse.jface.action.ContributionItem (You can use autocomplete for this).

The method that you have to override for a dynamic menu is fill(Menu menu, int index). In this method you have to create the new (dynamic) MenuItem. You can also simply return if (e.g. based on the selection) you do not want to show a menu item. In the example code below I simply display the current date in the dynamic menu item.

Do not forget to add a addSelectionListener to the MenuItem, to start some action when the menu is selected.

That's it.

The complete java source:

package com.sigasi;

import java.util.Date;

import org.eclipse.jface.action.ContributionItem;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;

public class MyDynamicMenu extends ContributionItem {

    public MyDynamicMenu() {
    }

    public MyDynamicMenu(String id) {
        super(id);
    }

    @Override
    public void fill(Menu menu, int index) {
        //Here you could get selection and decide what to do
        //You can also simply return if you do not want to show a menu

        //create the menu item
        MenuItem menuItem = new MenuItem(menu, SWT.CHECK, index);
        menuItem.setText("My menu item (" + new Date() + ")");
        menuItem.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                //what to do when menu is subsequently selected.
                System.err.println("Dynamic menu selected");
            }
        });
    }
}