以编程方式在Eclipse插件上添加上下文菜单

Question

我已经查看了几个类似的问题，但我无法解决此问题，我想在Project Explorer视图中右键单击项目或文件夹时，将子项添加到上下文菜单中。

我在plugin.xml中添加了根元素：

<extension
    point="org.eclipse.ui.menus">
  <menuContribution
     allPopups="true"
     class="com.my.menu.MyMenu"
     locationURI="popup:org.eclipse.ui.popup.any?after=additions">
  </menuContribution>

MyMenu类扩展了ExtensionContributionFactory，并且我覆盖了createContributionItems()方法，如下所示：

@Override
public void createContributionItems(final IServiceLocator serviceLocator, final IContributionRoot additions) {
    // build a command-based contribution parameters
    CommandContributionItemParameter pAA = new CommandContributionItemParameter(
            serviceLocator,
            "Submenu_CommandAA",
            "my.menu.root",
            SWT.PUSH);
    pAA.label = "Command AA";

    // create actual contribution items and add them to the given additions reference
    CommandContributionItem itemAA = new CommandContributionItem(pAA);
    itemAA.setVisible(true);
    additions.addContributionItem(itemAA, null);
}

然后，当我右键单击某个项目时，我收到此错误：

!MESSAGE Unable to create menu item "Submenu_CommandAA", command "my.menu.root" not defined