Infinitely scrolling list, how to update model?
Hello,
I have a basic setup: my model holds a list of VOs; service
loads data via a "getData" function, that takes count and offset as
parameters.
The Service dispatches a "loadComplete"-Event, when the data has
arrived. This Event, mapped to a command, updates the list in the
model.
I want to reload data, as the user scrolls a list. My Mediator
catches the "scrollreached"-Event on the component, and would call
"getData" with correct count and offset.
Question is - how does the LoadComplete-Command know, if he has to replace, or simply add the results to the models list?
I have some ideas in mind:
I could set the models list to length = 0, if I want new data. Then
the LoadComplete-Command would always add the new data, and not
replace it.
Or - in the mediator, register another command with the
LoadComplete-Event, that adds the data. But that seems too much
responsibility for a mediator...
I'm a bit confused :)
Thanks a lot for your help.
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Support Staff 1 Posted by Ondina D.F. on 16 Jul, 2012 08:17 AM
Hi Chris,
Sure, if it works for you, you can do that.
But, data paging for scrolling lists or data grids could get pretty complicated, depending on the requirements. If you are interested, you could do a research on the subject to get some inspiration.
Some keywords:
mx.collections.AsyncListView, paged collection, paged list, data page, lazy loading, lazy data structure, demand paging
Some links:
http://flexblog.faratasystems.com/2011/07/20/working-with-large-dat...
Not actionscript:
http://facestutorials.icefaces.org/tutorial/dataTable-JPA-tutorial....
http://wiki.apache.org/myfaces/WorkingWithLargeTables
HTH
Ondina
2 Posted by Chris on 27 Jul, 2012 06:27 PM
Hi Ondina,
Thanks for your reply, I forgot a little bit about this thread :)
The paging works fine, thanks for the links. Lazy Loading is what I do.
The situation has changed - as I only display items which have a short lifetime (in my Application) and are never changed, I don't store them in a model anymore.
Instead, I have created a viewmodel, which saves the state of the view with its items. This seems ok for me.
Chris
Support Staff 3 Posted by Ondina D.F. on 14 Aug, 2012 05:50 PM
No problem:)
Ondina D.F. closed this discussion on 14 Aug, 2012 05:50 PM.