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
>
