Re: Design for showing ridiculously huge number of images in Table View
Re: Design for showing ridiculously huge number of images in Table View
- Subject: Re: Design for showing ridiculously huge number of images in Table View
- From: Graham Cox <email@hidden>
- Date: Fri, 12 Dec 2008 22:17:45 +1100
On 12 Dec 2008, at 8:41 pm, rajesh wrote:
do I add observer at cell level OR the controller level ( dataSource
level ) ?
I am confused because the user might just scroll through the tabel ,
in first go there are definitely no images , at the same time the
cells which placed request for images might no longer be in the
visible-rect of the Outline Table && every cell receives
notification of every other image that got downloaded , so Is there
any way to determine if the current cell which just got notified to
determine if its in the visible-rect.
Just to make something clear: there is no cell *per row*, there is
only one cell *per column*. The cell is 'moved' from row to row to
draw its contents with new data for each row.
So registering for a notification at the cell level doesn't sound like
the right thing to do - scrolling makes some rows visible and others
no longer visible, but it's always the same cell.
I'd suggest that the way to do it is in the controller/datasource.
When an image is delivered from the server, the controller can figure
out what row that corresponds to and simply invalidate that row in the
table. If it's visible, the table will ask the datasource for the
image, which will now be available and can be returned immediately. If
the row isn't visible, the table will do nothing. So the scrolling
situation is taken care of automatically.
hth,
Graham
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden