Update Eclipse menu item enabled state

I created the menu item in the "File" menu as a command. For this command there is a handler implementing the IHandler interface. This handler contains the isEnabled method. I am trying to use this method to enable/disable my menu item, but that method is called only once 开发者_StackOverflowwhen I click on the "File" menu. When clicked for the second, third etc. times, the isEnabled method is not called again even if I changed the state of page (open/close editors) before.

What should I do? Maybe this method is not intended for control menu items?

Are you subclassing org.eclipse.core.commands.AbstractHandler? You should use setBaseEnabled(boolean) to update the state of your handler (which would update your command).

It's only valid to change enabled state in your handler as long as you also fire the HandlerEvent. It's usually easier to call setBaseEnabled(boolean) which will fire the event for you.

If you're trying to enable/disable the menu, than you should use core expressions. I've already explained how to do that in this answer:

Eclipse RCP menus & actions: Configure or code?

The part that you're interested in starts with:

For activating/deactivating a menu[...]

I hope this is what you're looking for.