根据Eclipse插件中视图的可见性使菜单条目可见吗？

Question

I want to realize the following:

In my Eclipse plugin I have a menu entry (realized by adding a command to the plugin.xml and a handler class). Pressing the entry triggers some actions which depend on data shown in a view (also provided by the plugin).

Now, if the view is closed, the actions can't be done. I therefore think it would be good style to disable the menu entry when the view is not visible.

I've found this article which descibes how to disable/enable menues, but I have no idea how to combine it with the visibility of the view.

Can someone help out with that?

Edit: I've solved my problem in a different way. But greg's answer should usually solve this problem, as also stated in the official eclipse documentation: http://help.eclipse.org/mars/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Fguide%2Fworkbench_cmd_expressions.htm

Answer 1

Use

<with variable="activePartId">
    <equals value="part id"/>
</with>

in the 'enabledWhen', 'activeWhen', or 'visibleWhen' expression (depending on exactly where you are using the expression).

For example to select when 'Project Explorer' is active:

<with variable="activePartId">
    <equals value="org.eclipse.ui.navigator.ProjectExplorer"/>
</with>