Re: [iPhone] Caching images fetched from a URL?
Re: [iPhone] Caching images fetched from a URL?
- Subject: Re: [iPhone] Caching images fetched from a URL?
- From: Luke the Hiesterman <email@hidden>
- Date: Wed, 13 May 2009 12:10:42 -0700
Yes, something like that. I should mention that it's probably best to
send in the NSIndexPath to the cell you're interested in rather than a
pointer to the cell itself. Then you can call [tableView
cellForRowAtIndexPath:indexPath] to get the cell just before your
performeSelectorOnMain thread. It might be nil, but that's ok, just so
long as you add the image data to your data source, so that if you
need to provide the image later inside your data source's
tableView:cellForRowAtIndexPath: method, you can.
Luke
On May 13, 2009, at 12:04 PM, Eric E. Dolecki wrote:
I haven't seen performSelectorOnMainThread before.
Should that call go into the selector method that's called? ie...
// This kicks off a thread
[NSThread detachNewThreadSelector:@selector(threadLoad:)
toTarget:self withObject:myArrayWithDictionary];
Now...
-(void)threadLoad:(id)param {
// param = the myArrayWithDictionary object I assume
// interogate the object and get vals, and then
[myCell performSelectorOnMainThread:@selector(setImage:)
withObject:myImage waitUntilDone:YES];
}
?
On Wed, May 13, 2009 at 2:53 PM, Luke the Hiesterman <email@hidden
> wrote:
On May 13, 2009, at 11:45 AM, Eric E. Dolecki wrote:
So is it safe to approach threads like they were timers? You start a
thread, and it calls back to it's selector method when it's complete
(detachNewThreadSelector:toTarget:withObject)?
I would conclude my thread with a line like:
[myCell performSelectorOnMainThread:@selector(setImage:)
withObject:myImage waitUntilDone:YES];
That should set your cell's image to the image you just downloaded.
Now - what if a thread completes and the cell is currently out of
view (it was scrolled) - do the internals take care of that, or
could it cause an error?
I wouldn't worry about setting cells to images that are out of view.
An implementation that waits for cells to come back into view would
be tedious and probably unnecessary.
Luke
--
http://ericd.net
Interactive design and development
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