2009-03-21
ljm189
发件人： markdsievers
发送时间： 2009-03-21 08:02:53
收件人： Android Developers
抄送：
主题： [android-developers] Re: ListViews getting rendered multiple times
Hi Romain,
Thanks for your response, though I had a couple of questions for you;
1) None of the LinearLayout's contain the layout_wieght attribute...So
I'm not sure that's my problem.
2) Could you please breifly explain the logic behind why the framework
requires n passes over the ListViws items?
3) Give that this is an overhead, can you suggest an approach that
does not suffer this?
Thanks in advance,
Mark Sievers
On Mar 18, 4:09燼m, Romain Guy <[email protected] > wrote:
> This is expected if you use layout_weight in your linearlayout for instance.
>
>
>
> On Mon, Mar 16, 2009 at 7:42 PM, markdsievers <[email protected] >
> wrote:
>
> > So the situation is this, I have aListViewthat is embedded in two
> > LinearLayout ViewGroups to form a screen. BaseAdapter.getView() (the
> > implementation of the ListAdapter) is typically called n times (where
> > n is numElements) to render the screen. The problem I have is this set
> > of calls is being repeated for every ViewGroup that the list is
> > contained in...So for a Layout like this:
>
> > -LinearLayout
> > --Linearlayout
> > ---ListView
>
> > The adapters getView() is being called n*3 times (3 = 1 for the parent
> > LinerarLayout, one for the child LinearLayout and one for the List
> > itself).
>
> > This is obvisouly a problem when the items in the List are expensive
> > to build (even with recycling).
>
> > So Im looking for some guidance on this, as the documentation doesnt
> > seem to note this behaviour from what I can see.
>
> > A small, basic example of the source is located on my post here
> >http://www.anddev.org/listview_getting_rendered_multiple_times-t5290....
> > with more details aswel as a ready made eclipse project(also attached
> > below) if anyone is keen to try it out.
>
> --
> Romain Guy
> Android framework engineer
> [email protected]
>
> Note: please don't send private questions to me, as I don't have time
> to provide private support. 燗ll such questions should be posted on
> public forums, where I and others can see and answer them
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en
-~----------~----~----~----~------~----~------~--~---
