RE: User interfaces using XML

[Paul Hepworth <phepworth s-vision com>]

> One problem I see with your version is that the entire structure of the 
> interface will be different if the user changes the XML. Your system only 
> seems to cater for communication of commands from the interface to the 
> application, making it unable to cope with things like switching off
> certain 
> commands at certain times since the application and 'interface provider'
> will 
> have no agreed way of accessing any particular element.
> 
> Mind you, if this problem could be resolved then the idea of different XML
> 
> documents for different types of interface would be better to provide a
> closer 
> fit to the actual interface shown. The casading stylesheet idea is
> probably a 
> little to complex and unwieldy
> 
> 
Actually, any component can be assigned a name (name="FileOpen" for
example), and the application can send messages to the component by name.
(Ex:  application sends "disable FileOpen" to the UI engine, which sends the
"disable" message to all components named "FileOpen" -- typically a menu
item and a toolbar button.)  (Likewise, entry-fields will respond to
messages such as setText, getSelection, etc.;  canvases will respond to
moveTo, lineTo, fill, etc.)  (Some form of shared memory would be desirable
-- especially for things such as setText for multiline entry fields, but
these are implementation details.)
Naturally, an application must specify what commands it accepts and what
named components it expects to exist so that the XML author knows what is
available and what to make available.


Paul