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[solved] Enable buttons [message #766838]

Fri, 16 December 2011 09:14

Eclipse User

Hey there,

I'm trying to enable some buttons in my toolbar after some action has been executed.

The plugin.xml looks like this:
The command to be enabled:

<command
    id="piOptimize.commands.doOneIteration"
    name="doOneIteration">
</command>

The Handler:

<extension
    point="org.eclipse.ui.handlers">
        <handler
            class="pioptimize.commands.DoOneIteration"
            commandId="piOptimize.commands.doOneIteration">
        </handler>
</extension>

And the contribution to the toolbar:

<command
    commandId="piOptimize.commands.doOneIteration"
    icon="icons/run_next.png"
    style="push">
</command>

The command which is supposed to enable the button calls:
DoOneIteration.setEnabled(true);

This call does not have an immediate effect and I can't figure out why.
Is there a way to force the toolbar to redraw itself? It does so if I call an instance of TitleAreaDialog, but that's not the desired behaviour, the buttons are supposed to be enabled after I setEnabled(true).

It does not work with an <enableWhen> in the xml either, the change is not immediate.

I would be very pleased, if someone helped me!

[Updated on: Sat, 17 December 2011 07:56] by Moderator

Re: Enable buttons [message #766975 is a reply to message #766838]

Fri, 16 December 2011 14:30

Eclipse User

DoOneIteration should subclass AbstractHandler and use setBaseEnabled(*). Either that, or you have to fire the handler change event yourself. Read the javadoc for IHandler.

PW

Re: Enable buttons [message #767235 is a reply to message #766838]

Sat, 17 December 2011 06:57

Eclipse User

DoOneIteration subclasses AbstractHandler now and the class responsible for changing the state of DoOneIteration calls

button.setBaseEnabled(true);

setBaseEnabled(boolean state)

simply calls

super.setBaseEnabled(state)

which fires

fireHandlerChanged(new HandlerEvent(this, true, false));

The isEnabled() method of DoOneIteration returns super.isEnabled().

The mechanism works fine when I start a new wizard, but still, the enablement is not changed immediately.
That kind of makes sense, because calling hasListeners() always returns false.
Who is supposed to listen to this event?

Edit: I got it!
I implemented the constructor and let it add a handler:

class EnablementListener implements IHandlerListener {
	boolean lastChange = false;
	public void handlerChanged(HandlerEvent handlerEvent) {
		lastChange = handlerEvent.isEnabledChanged();
	}
}

So the constructor now looks like this:

public DoOneIteration(){
    Activator.getDefault().addButtons(this);
    setBaseEnabled(false);
    addHandlerListener(new EnablementListener());
}

And it works Smile

Thank you for your help!

Edit2 (for completeness' sake): addHandlerListener calls super.addHanderListener, in case someone having the same problem reads this thread.

[Updated on: Sat, 17 December 2011 07:58] by Moderator

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