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Problems with command expressions and enableWhen, activeWhen [message #495812]

Fri, 06 November 2009 04:07

Eclipse User

Hi @ll,

first of all I think I have a problem using enableWhen and activeWhen combined with commands. Maybe someone can give me a reference where I find more information when to use which of the expressions.

The concrete problem is: I have created a view which works perfectly. Now I have added a command and a key binding. The command should be always executed when ENTER is pressed.
Now I have the problem that always ENTER is pressed and the view is not active the command is executed. So I tried it with enableWhen and activeWhen that the command is only activated if the viewPart is in focus or active:

The code in XML looks as follows:

<handler
commandId="de.genesys_e.trace.ui.command.analyze">
<enabledWhen>
<with
variable="activePart">
<iterate>
<instanceof
value="de.genesys_e.trace.ui.views.AnalyzerView">
</instanceof>
</iterate>
</with>
</enabledWhen>
<activeWhen>
<with
variable="activePart">
<iterate>
<instanceof
value="de.genesys_e.trace.ui.views.AnalyzerView">
</instanceof>
</iterate>
</with>
</activeWhen>
</handler>

But it does not work. So, maybe someone can tell me what's wrong?!

Bjoern

Re: Problems with command expressions and enableWhen, activeWhen [message #495815 is a reply to message #495812]

Fri, 06 November 2009 04:17

Eclipse User

Hi,

Dont use activePart and instanceof. Try to use activePartId and compare it (equals) my.view.id

i.e.:
<handler
commandId="de.genesys_e.trace.ui.command.analyze">
    <enabledWhen>
    <with
        variable="activePartId">
    <equals>
    value="de.genesys_e.trace.ui.views.AnalyzerView"> <- insert your view id here
    </equals>
    </with>
    </enabledWhen>
</handler>

[Updated on: Fri, 06 November 2009 04:19] by Moderator

Re: Problems with command expressions and enableWhen, activeWhen [message #495827 is a reply to message #495815]

Fri, 06 November 2009 05:17

Eclipse User

Thank you for the fast response. I have tested it, but it does not work. The command ist still active when the view is not in the foreground and it is also active when the view is closed.

That's confusing...

Re: Problems with command expressions and enableWhen, activeWhen [message #495828 is a reply to message #495827]

Fri, 06 November 2009 05:25

Eclipse User

Be careful, you have to do that for all F5 Handlers. Did you check which handler will be executed when your view is closed? Is it still the one where you added the activeWhen and EnabledWhen expression?

The problem is often that a menu entry won´t be grayed out because there is a handler which is always active (because an enabledWhen and activeWhen expression was not declared).

Like mentioned before make a System.out.println() in your execute Method and check which handler will be executed if the view has no Focus or was already closed.

Greetz
Thomas

Re: Problems with command expressions and enableWhen, activeWhen [message #495829 is a reply to message #495828]

Fri, 06 November 2009 05:42

Eclipse User

It is the same Handler, I have defined under org.eclipse.ui.handlers:

<handler          class="de.genesys_e.trace.ui.commands.AnalyzeHandler"
   commandId="de.genesys_e.trace.ui.command.analyze">
         <enabledWhen>
            <with
                  variable="activePartId">
               <equals
                     value="de.genesys_e.trace.views.analyzer">
               </equals>
            </with>
         </enabledWhen>
         <activeWhen>
            <with
                  variable="activePartId">
               <equals
                     value="de.genesys_e.trace.views.analyzer">
               </equals>
            </with>
         </activeWhen>
      </handler>

And if the view is closed the Handler is still executed. Is this a problem of extending AbstractHandler and not overriding isEnabled...?

Re: Problems with command expressions and enableWhen, activeWhen [message #495851 is a reply to message #495829]

Fri, 06 November 2009 07:01

Eclipse User

hey,

no its definitely not a problem of not overwriting isEnabled(). I just the same mechanism and it works perfectely.

Maybe there is something wrong with your keybinding? How do you realize that the handler will be executed when ENTER is pressed?

Re: Problems with command expressions and enableWhen, activeWhen [message #495865 is a reply to message #495851]

Fri, 06 November 2009 07:55

Eclipse User

Therefore I used org.eclipse.ui.bindings:

<extension
         point="org.eclipse.ui.bindings">
      <key
            commandId="de.genesys_e.trace.ui.command.analyze"
            contextId="org.eclipse.ui.contexts.window"
            schemeId="org.eclipse.ui.defaultAcceleratorConfiguration"
            sequence="CR">
      </key>
</extension>

Is it a problem with contextId?

Re: Problems with command expressions and enableWhen, activeWhen [message #495868 is a reply to message #495865]

Fri, 06 November 2009 08:15

Eclipse User

Hmm no i have same contextId and for me it works... but maybe its because of the CR. Did you try it with something else, i.e. F5 ?

I´m not sure but CR is very special and i wouldn´t be surprised if something going wrong there...

If this also doesnt work, the scheme id could also be the problem. We defined our own scheme id, so maybe try that.
Greetz
Thomas

Re: Problems with command expressions and enableWhen, activeWhen [message #495937 is a reply to message #495812]

Fri, 06 November 2009 12:44

Eclipse User

Where is your command definition, from org.eclipse.ui.commands?

If you had a defaultHandler, for example, that would always be active.

PW

Re: Problems with command expressions and enableWhen, activeWhen [message #496171 is a reply to message #495937]

Mon, 09 November 2009 04:25

Eclipse User

Sorry for the late reply but it was weekend and I had no access to the code. In my command definition I do not use a defaultHandler now. I had defined a defaultHandler for each command wich was my own Handler class. Very silly...

So, to sum it up:

1. I have to define my Handler below org.eclipse.ui.handlers with a class and an ID.

2. Then I define my command. If I need a defaultHandler which is always active, I define it in the command using the field defaultHandler.

3. After all I define my key bindings.

If I don't use a defaultHandler I can use activeWhen and enabledWhen to manipulate the state of a command (e.g. grayed out)?!

Am I right so far?

Björn

Re: Problems with command expressions and enableWhen, activeWhen [message #496843 is a reply to message #496171]

Wed, 11 November 2009 09:30

Eclipse User

Bjoern Berg wrote on Mon, 09 November 2009 04:25

If I don't use a defaultHandler I can use activeWhen and enabledWhen to manipulate the state of a command (e.g. grayed out)?!

Björn

That's mostly it. Just a quick note on activeWhen and enabledWhen.

A command can only have one active handler at a time. That's where activeWhen comes in. Those expressions are evaluated on all handlers for a command (like copy) and the output is a 2 or 3 handlers that can be active. Then they are prioritized (based on a system like the numbers in org.eclipse.ui.ISources). Then one is picked.

That handler can then be enabled or disabled, and that determines the state of the command.

If no handler is picked (because none were candidates or because 2 or more had the same, highest priority) then the command is disabled.

So to recap: Use activeWhen to determine when your handler should be the behaviour for a command. Then use enabledWhen to determine if it is enabled/disabled.

PW

Re: Problems with command expressions and enableWhen, activeWhen [message #779829 is a reply to message #496843]

Mon, 16 January 2012 11:28

Eclipse User

Hi,
thanks for this post - helped me define a tricky context menu enablement.

Ta,
Mark.

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