Re: UITable Views and display lags
Re: UITable Views and display lags
- Subject: Re: UITable Views and display lags
- From: Michael Davey <email@hidden>
- Date: Fri, 19 Mar 2010 20:38:59 +0000
That worked a treat - thanks. I was already aware of the threading issues as have developed for the Mac before, but thanks for the heads up
On 19 Mar 2010, at 17:55, WT wrote:
> On Mar 19, 2010, at 6:40 PM, Michael Davey wrote:
>
>> OK, so I have changed the code to show a placeholder image, but I am a little uncertain as to how to fetch the images asynchronously. I could start a background thread with performSelectorInBackground, but am concerned that this would spawn far too many threads - does anyone have any suggestions?
>
> You might want to use an NSOperationQueue. Define NSOperation instances, each fetching one or more images. For each fetching NSOperation you define, you should also define a "cleanup" NSOperation, dependent on its associated fetching one, so that when the fetching one ends, the cleanup one then swaps the placeholder image out and the fetched images in. Make sure, though, that this swap happens in the main thread, meaning that the cleanup NSOperation should invoke a -performSelectorInMainThread method, rather than access the UI directly.
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