AFAIK, a thread can not access UI components. But I want to preload images in a background thread and then display these in an UIImageView. Do I have to use special methods to access UIImageView in the main thread then?
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AFAIK, a thread can not access UI components. But I want to preload images in a background thread and then display these in an UIImageView. Do I have to use special methods to access UIImageView in the main thread then?
If I understood your question correctly, you’re half correct. Threads can access UI components, but only the main thread can do it reliably. Your background thread can use
performSelectorOnMainThread:withObject:waitUntilDone:to call up selectors in the main thread, and from those selectors interact with the UI.Example:
[self performSelectorOnMainThread:@selector(updateImage) withObject:nil waitUntilDone:YES];