Hi Greg,

How would one specify multiple named styles for a component element?  Like

<PushButton styles="redButton bigFont"/>

Cheers,

Michael

On Fri, 2 Jul 2010, Greg Brown wrote:

Hi all,

I have been thinking about this and I think I have a fairly elegant solution that will also 
significantly extend the capabilities of BXMLSerializer. I am thinking of extending the 
<bxml:include> tag to support loading of arbitrary content. Currently, it only supports 
includes of other BXML files, but there is no reason that it couldn't be modified to include 
other types, such as JSON, XML, or even images. All we'd have to do is determine an appropriate 
serializer to use for the include - this could be inferred based on file extension or could be 
specified explicitly via a "mimeType" attribute to the include tag. The MIME 
type-to-serializer mappings could be configurable such that an include could literally be used 
to load any type of object.

One application of such an extension would be styling. <bxml:include> could be used to load a "stylesheet" - a JSON 
file containing a "map of maps". The format of this file would be identical to the format I had been considering for the 
"named styles" approach - each key/value pair in the file would essentially represent a "style class". For example, 
the following JSON file would define a "redButton" class:

{   redButton: {
       backgroundColor: "#aa0000",
       color: "#ffffff"
   }
}

In a BXML document, this file could be included as follows:

<bxml:include bxml:id="styles" src="styles.json"/>

The "redButton" style could then be applied to a button as follows:

<PushButton styles="$styles.redButton"/>

Unlike the previous solution I proposed, this approach would require no changes to 
the Component or Container classes whatsoever. With the exception of extending the 
<bxml:include> tag, it relies entirely on existing functionality (and existing 
BXML syntax, so developers will already be familiar with it).

There are obviously other applications as well. Some simple examples:

<TableView>
   <tableData>
       <bxml:include src="table_data.json"/>
   </tableData>
</TableView>

<TreeView>
   <treeData>
       <bxml:include src="tree_data.xml"/>
   </treeData>
</TreeView>

One challenge might be how to specify the MIME/serializer mapping for an 
include (we won't want BXMLSerializer to include all possible mappings by 
default). This could be inherited from the parent serializer, but I think that 
a BXML syntax for specifying it in markup is probably a good idea.

Anyway, I think this would be an extremely flexible and useful addition to the 
serializer, and I think it also handles the styling case pretty well. Let me 
know what you think.

G


On Jul 2, 2010, at 1:34 PM, Greg Brown wrote:

FYI, named styles are turning out to be a lot more challenging than I expected. 
The solution I proposed the other day doesn't work - elements in BXML aren't 
added to the parent element until the end tag is processed. So, given the 
following structure:

<Window styleClasses="{foo:{...}}">
 <BoxPane>
   <PushButton styleClass="foo"/>
 </BoxPane>
</Window>

when the styleClass attribute of the PushButton is processed, the BoxPane hasn't yet been 
added to the Window, so the "foo" style class name resolves to null.  :-(

I'll keep thinking about it, though. Suggestions are welcome.

Thanks,
G


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