--- In flexcoders@yahoogroups.com, "Seth Hodgson" <[EMAIL PROTECTED]> wrote:
>
> You can put anything you like into the body, or headers, of an
AsyncMessage; a string, a number, an anonymous Object, a typed Object
(if you use a typed Object be sure to tag it with [RemoteClass]
metadata). You can control which subscribed Consumers receive the
message by using the Consumer.selector property (a SQL-92 expression
evaluated on the server against the headers of incoming messages; if
the message headers satisfy the expression the message will be
delivered to the Consumer), or by using the Consumer.subtopic property
to subscribe to a subtopic (or range of subtopics) within a
destination and using the Producer.subtopic property to control which
specific subtopic sent messages go to.
>
> When building 'screen-sharing' style applications like this, you
need to really keep network latency in mind. Some GUI frameworks will
'summarize' events before handing off to even local processing (i.e.
collapsing a bunch of individual key strokes into a summary string
containing all the characters typed since the last event dispatch and
just dispatching that single event). This becomes even more important
when you're considering sending lots of high frequency events over the
network to peers.
>
> In this case, I'd recommend sending a single message to subscribed
peers on drop complete, indicating which component was dragged and
dropped along with its final location. You can then either just
reparent the corresponding component immediately on the receiving
peer, or animate it along a simple path. There are lots of options
with this sort of thing, but you shouldn't try to generate and send a
message for each pixel it is dragged.
>
> Hope that helps,
> Seth
>
> From: flexcoders@yahoogroups.com [mailto:[EMAIL PROTECTED]
On Behalf Of jeffreyr6915
> Sent: Wednesday, May 14, 2008 11:01 PM
> To: flexcoders@yahoogroups.com
> Subject: [flexcoders] Flex Messaging Service + Drag and Drop List
Component
>
> I have a 2 list components in which I have enabled drag and drop
> (dragEnabled="true" dropEnabled="true" dragMoveEnabled="true"
> dragDrop="dragDropHandler(event)"). So, I am able to drag and drop the
> List items (which I have a custom itemRenderer for). I am also using
> flex messaging service (Flex data services) so that a change made in
> one connected client/browser is propagated to all other connected
> browsers. I would like to be able to drag an item from one list to
> another (in one browser) and see that drag and drop happen (as it is
> happening) in all other connected browsers. I know that I need to send
> an AsyncMessage to the server via a producer, and receive from the
> server via a consumer.
>
> Question: What do I include in the async message in order to see the
> list items drag/drop as it is happening in all connected browsers?
>
> Can someone help me with code/example? Thanks
>
Thanks Seth, this helps a lot. But I am unclear on exactly what should
be sent to the server inside of AsyncMessage. Below I have my drop
handler and message handler. I am very new to Flex and I do not
understand what to do in the message handler (i.e., where to set the
received data) so that the consumers can actually see the drag an drop
action happening. What do you mean by animate the item dragged along
the simple path? I am using the built in drag and drop capabilities of
ther List component. Can you please help me with my code? Thanks
private function dragDropHandler(event:DragEvent):void
{
// Get the drop target component
var dropTarget:List = event.currentTarget as List;
//Get dragged item
var draggedItem:CustomImageRenderer = event.draggedItem
as CustomImageRenderer;
//Send the message to the server
message = new AsyncMessage();
message.headers.dropTarget = dropTarget;
message.headers.draggedItem = draggedItem;
producer.send(message);
}
private function messageHandler(event:MessageEvent):void
{
//WHAT DO I DO HERE?
}
-- Jeffrey
