Refresh menu item in view

Question

Context

I'm building a plugin for eclipse 3.4 and more. I have a view with id mrp.view with a menuContribution set to toolbar:mrp.view . This menuContribution has some command, and I have this one:

<handler
    class="mrp.handlers.export"
    commandId="mrp.commands.export">
</handler>

<command
    commandId="mrp.commands.export"
    label="My command"
    style="push">
</command>

My handler, mrp.handlers.export has a dynamic ìsEnabled()` method, looking like that :

@Override
public boolean isEnabled() {
    return !getMySelection().isEmpty();
}

Question

How can I refresh the button on my toolbar when data changed ? (refresh is done automatically if I click anothr button of the toolbar, but if I don't...)

I tried..

ICommandService service = (ICommandService) PlatformUI.getWorkbench().getService(ICommandService.class);
service.refreshElements("mrp.commands.export", null);

But it doesn't seems to do anything.

Also this one:

public class Export extends AbstractHandler implements PropertyChangeListener {

@Override
public void propertyChange(PropertyChangeEvent evt) {
    setBaseEnabled(!getSelection().isEmpty());
}

    // ....
}

It is called, but the icon on my view's menu is not refreshed (on eclipse 3.7). Did I do something wrong ?

Answer 1

Your handler must fire an event when it's enablement changes. If you have the change update your handler using org.eclipse.core.commands.AbstractHandler.setBaseEnabled(boolean) it will fire the required event.

Answer 2

Thanls to Paul Webster's answer, I got it working.

public class Export extends AbstractHandler implements PropertyChangeListener {
    public Export() {
        Activator.getDefault().AddListener(this);
        setBaseEnabled(!getMySelection().isEmpty());
    }

    @Override
    public Object execute(ExecutionEvent event) throws ExecutionException {
        // My handler
        return null;
    }

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        if (evt.getPropertyName().equals(Activator.EVENT_SELECTION_CHANGED)) {
            boolean before = isEnabled();
            boolean after = !getMySelection().isEmpty();

            if (after != before) {
                setBaseEnabled(after);
            }
        }
    }
}