Thanks George, That's an interesting idea, but when I tried it, I found that the invisible gif I used was not invisible in the editor. It might work if I used one that matched my background color. However, the 2 second delay that you mention, and which I observed, make it not really usable. In any case, it is still quite a convoluted way to achieve something I think should be simple if you want to create an input form interface rather than a traditional document interface, which, as you know, is something I advocate strongly. I don't know what the answer is -- a custom CSS selector, a schema-aware fragment insert operation that greys the button if the insert would be invalid, a deactivate-button action -- but I think something is needed to complete the promise of the brilliant forms capability you have created. Thanks, Mark -----Original Message----- From: George Cristian Bina [mailto:george@oxygenxml.com] Sent: February-26-13 6:16 PM To: Mark Baker Cc: oxygen-user@oxygenxml.com Subject: Re: [oXygen-user] What is "When this XPath expression is true" action parameter relative to? Hi Mark, There is an oxy_xpath() extension function (not a selector) that can be used to get an interesting behavior. I still use my section/title example below so you should adapt this to your actual elements: section:before { content: oxy_button( actionID, oxy_xpath('if (./title) then "delete.title" else "add.title"'), transparent, true); } So, basically I can use the oxy_xpath() function to dynamically create the action name based on an XPath condition, in this case I check if a title child element exists or not, but you can have any complex XPath 2.0 expression there and cascade multiple if statements if needed. The only issue right now is that it takes about 2 seconds for the action to change into the other after it is invoked - we probably need to look into speeding that up - but the functionality is there and it should cover your use case. To get the action disappear I think that instead of the delete action you can define an action that does not do anything and that has a small invisible icon and return that action instead of the delete one, but I have not tested this. Best Regards, George -- George Cristian Bina <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger http://www.oxygenxml.com On 2/26/13 9:44 PM, Mark Baker wrote:
Hi George,
Thanks for the wonderfully detailed response. This information definitely needs to be in the documentation.
Here's what I am trying to do. I have an element <operational-failure> that has a compulsory element <description>, and an optional element <occurrence>. In my CSS, I have a button attached to operational-failure:after that allows the author to add an <occurrence> element.
The occurrence element is allowed only once, so once the occurrence element had been added, I would like to do one of the following, in order of preference:
* Hide the button altogether. * Disable the button (grey it out). * Display an informative message when the button is pressed.
Because the <operational-failure> element is not empty, the empty selector doesn't seem to help me achieve the first option.
Putting in an XPath test of "not(occurrence)" does not give me the second option (greying out the button), but it does give me the third option, in a generic way. But the message is not really appropriate for use with a button. It says:
"The action +occurrence is not available in the current location"
That would make sense if the user was selecting an action from a menu, and had placed their caret where they want the action to occur. With a button, though, the user does not know that an "action" is being invoked, and they have no control over the location where the action takes place -- that is dictated by the button. So the message does not really tell the user why the button action can't be completed.
Actually, the message they get without the button action being disabled is actually more informative, because then they get the "element not allowed at this location" dialog.
Neither of these is really satisfactory, though, because it is a universal interface convention that if an operation is unavailable, the button/menu that performs it should either be hidden or unavailable (greyed-out).
I haven't got my head around the XSLT Operation yet, so I'm not sure if it provides a solution.
What I can suggest as ways to address this class of problem are:
* an oXygen CSS extension for selecting elements based on their child elements
* if a button is attached to an unavailable action, grey out the button
* provide a way to specify a custom message when an action is not available in a particular context
Thanks for your help,
Mark
-----Original Message----- From: George Cristian Bina [mailto:george@oxygenxml.com] Sent: February-26-13 1:45 PM To: Mark Baker Cc: oxygen-user@oxygenxml.com Subject: Re: [oXygen-user] What is "When this XPath expression is true" action parameter relative to?
Hi Mark,
As you move the caret in the document the element that contains the caret becomes the current element where that XPath expression is evaluated.
Let's assume we have a section element that should contain a title element and we define an add.title action that adds the title element in the section. We can do this using the
ro.sync.ecss.extensions.commons.operations.InsertFragmentOperation
with the following parameters:
Fragment: <title></title> Insert location: ancestor-or-self::section Insert position: Inside as first child
and we can make this action available when we are inside a section, by setting the "when this XPath expression is true" field to
ancestor-or-self::section
Now, if the section defines only one title then we can enhance the condition to
ancestor-or-self::section[not(title)]
and the action will become active only when the caret is in a section without a title.
When an action is contributed to the Author page though the oxy_button() CSS extension function then the context for the XPath expression is the element on which we added the button.
For example, we can add this action on the before pseudo-element of a section, like below:
section:before { content: oxy_button( actionID, "add.title", transparent, true);
This will add the title element on a section without a title and on a section with title it will give a message that the action is not available anymore in that context - we disable the action on the toolbar when it is not available but this was not implemented when the actions are added inline in the author.
In version 14.2 we added support for :empty selectors so you may want to see if that is useful for your use case. For example if I modify the above CSS rule to match an empty section
section:empty { content: oxy_button( actionID, "add.title", transparent, true); }
then the behavior is nice, as I get a button if the section is empty, I press the button and I get the title while the button disappears.
Another thing that you may want to investigate is the XSLTOperation. This allows you to use an XSLT stylesheet to specify what the operation will actually do. The XSLT script can be something like
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0"> <xsl:include href="scripts/action1.xsl"/> </xsl:stylesheet>
and the include will be resolved relative to the framework file location, so then you will add in your framework folder
scripts/action1.xsl
and edit that stylesheet to actually implement the processing you want. The advantage of doing this is that you can interactively develop and test the action: you can change the action1.xsl, save it, invoke the action in the XML document the Author mode, undo if you are not happy with the result, change the XSLT file again, try again the action, and so on.
Maybe if you can provide some more details about what you want to do we can provide better advise.
Best Regards, George -- George Cristian Bina <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger http://www.oxygenxml.com
On 2/26/13 7:07 PM, Mark Baker wrote:
What is the "When this XPath expression is true" parameter of an action definition evaluated relative to? The docs just say "an XPath expression that applies to elements and attributes;" but they don't say what the current element is at the time the xpath is evaluated.
My reason for asking is this: I want to create a button to add an element to a document. But since this element is only allowed once inside its parent element, I would like the button to either disappear or be disabled if the parent element already contains the element that the button inserts.
Ideally, I would like to do this using the stylesheet to remove the button when the child element already exists, but CSS does not provide a selector for an element that contains (or does not contain) another element, so there does not seem to be a way to do that. (Enhancement request for an Oxygen CSS extension for this purpose)
So since that does not work, my next approach is to invalidate the button if the child element already exists. To do this, I think I would need the "When this XPath expression is true" parameter to be evaluated relative to the path specified in the "insertLocation" parameter, but that does not seem to be how it works.
So, what is the current element when "When this XPath expression is true" parameter is evaluated.
And, more generally, can anyone think of a way to do what I am trying to do here?
Thanks,
Mark
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