Ok, I've learned a little more. When you re-enable auto updates,
ListCollectionView.handlePendingUpdates() is called. This function
optimizes row-update operations, combining them into a single event,
but row-add operations get handled one by one. So the adds are no
more efficient with auto-updates disabled than enabled.
Is there any way to refresh the entire list, and prevent the update
queue from being flushed? I tried calling refresh() before
enableAutoUpdates(), but it actually prevents the update from
happening at all. Rows only get added in the visible area -- no
scrollbar is created until I collapse and expand the parent node.
--- In flexcoders@yahoogroups.com, "whatabrain" <[EMAIL PROTECTED]> wrote:
>
> Sorry for cluttering the group...
>
> I found one more detail. If, instead of disabling auto-update on
the
> root node, I do it on the first (and currently only) child node:
>
> gridData[0].children.disableAutoUpdate();
>
> and don't re-enable updates, rows still get added, but only up to
the
> limit of the AdvancedDataGrid's current scroll area. If I then
> collapse and expand the root, I see all the rows.
>
> If I do enable auto-update later on the child, the rows get drawn,
> but it takes even longer than without this trick (14 seconds
instead
> of 8).
>
>
>
> --- In flexcoders@yahoogroups.com, "whatabrain" <junk1@> wrote:
> >
> > Huh. I just noticed that when I comment out the line that calls
> > enableAutoUpdate(), auto-update still happens. This tells me I'm
> > doing something wrong. Any ideas?
> >
> >
> >
> > --- In flexcoders@yahoogroups.com, "whatabrain" <junk1@> wrote:
> > >
> > > Replacing the dataProvider isn't the best option for my
> particular
> > > application, since requests to add rows will come in at random
> > > intervals, and I don't want to lose selection state and such.
> > >
> > > So I've written the code such that, if two add requests happen
> > within
> > > 300ms of each other, I call disableAutoUpdate. If, after that,
> > 500ms
> > > go by with no add requests, I call enableAutoUpdate().
> > >
> > > But now, adding 1000 rows takes just as long as before. With
the
> > tree
> > > collapsed (or with a regular DataGrid), it takes 1 second. With
> the
> > > tree opened, it takes 8, with or without auto-update.
> > >
> > > Any idea why this might be? I can switch to replacing the
> > > dataProvider and only running this optimization when the app
> first
> > > loads, but I'd rather not.
> > >
> > > More information: The dataProvider is a subclass of
> > ArrayCollection,
> > > which contains objects with a "children" member, which is
another
> > > ArrayCollection.
> > >
> > >
> > > private var m_lastAdd:Number = 0;
> > > private var m_autoUpdateEnabled:Boolean = true;
> > >
> > > // This is called 1000 times
> > > private function AddItem(name:String):void
> > > {
> > > var now:Number = (new Date()).getTime();
> > > if (m_autoUpdateEnabled && (now - m_lastAdd < 300))
> > > {
> > > gridData.disableAutoUpdate();
> > > m_autoUpdateEnabled = false;
> > > setTimeout(flushAddQueue, 500);
> > > }
> > > m_lastAdd = now;
> > > [Then call the add function, which puts items into the 0th
group]
> > > }
> > >
> > > private function flushAddQueue():void
> > > {
> > > if (!m_autoUpdateEnabled && ((new Date()).getTime() - m_lastAdd
<
> > > 300))
> > > {
> > > gridData.enableAutoUpdate();
> > > m_autoUpdateEnabled = true;
> > > }
> > > else
> > > setTimeout(flushAddQueue, 500);
> > > }
> > >
> > >
> > >
> > > Thanks for all your help so far!
> > >
> > >
> > > --- In flexcoders@yahoogroups.com, "Daniel Gold" <danielggold@>
> > > wrote:
> > > >
> > > > I've seen a lot of posts with performance related to using
> > Bindable
> > > > Collections like that. One of the dangerous of having such a
> > useful
> > > easy API
> > > > for updating controls...
> > > >
> > > > Just to expand on what Alex is suggesting, suppose your
service
> > > call returns
> > > > to a function called updateData, and your control is bound to
a
> > > _data
> > > > ArrayCollection
> > > >
> > > > public function updateData(newData:IList):void
> > > > {
> > > > var newData:Array =[];
> > > > for each(var data:Object in IList)
> > > > {
> > > > _newData.push(data);
> > > > }
> > > > _data.source = newData;
> > > > _data.refresh();
> > > > }
> > > >
> > > > That's an extremely basic code example, and actually
> unnecessary
> > to
> > > loop
> > > > like that in most cases, but basic principle is get your data
> > > structured in
> > > > an Array or similar structure, add new items, remove old
> > > unnecessary items,
> > > > whatever you need to do, concat or replace the source Array
of
> > your
> > > > ArrayCollection, and then call refresh which will dispatch a
> > > > COLLECTION_CHANGE event which will trigger any controls using
> it
> > as
> > > a
> > > > dataProvider to update.
> > > >
> > > > On Thu, Jul 31, 2008 at 6:47 PM, Alex Harui <aharui@> wrote:
> > > >
> > > > > There is enable/disableAutoUpdate, but adding rows one
at
> a
> > > time is
> > > > > inefficient. Just concat the two arrays and replace the
> > > dataprovider
> > > > >
> > > > >
> > > > > ------------------------------
> > > > >
> > > > > *From:* flexcoders@yahoogroups.com
> > > [mailto:[EMAIL PROTECTED] *On
> > > > > Behalf Of *whatabrain
> > > > > *Sent:* Thursday, July 31, 2008 3:23 PM
> > > > > *To:* flexcoders@yahoogroups.com
> > > > > *Subject:* [flexcoders] How to temporarily stop a
> dataProvider
> > > from
> > > > > updating UI
> > > > >
> > > > >
> > > > >
> > > > > I've found that adding a lot of rows (1000+) to an
> > > AdvancedDataGrid can
> > > > > be quite slow, if the rows happen to be visible (in an open
> > node
> > > of the
> > > > > tree). I don't know why this is the case, especially since
> it's
> > > not the
> > > > > case in a regular DataGrid, but I'd like to work around it.
> > > > >
> > > > > So how can I tell the AdvancedDataGrid to temporarily
ignore
> > > updates to
> > > > > the dataProvider? Once the large number of rows have been
> > added,
> > > I'll
> > > > > turn the automatic updating back on, for the slow trickle
of
> > > updates
> > > > > that come after that.
> > > > >
> > > > >
> > > > >
> > > >
> > >
> >
>
