UITableView not responding to performSelectorOnMainThread
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I set up a UITableView that is supposed to display some information once certain data is loaded from a website. In order for the UI to update and the data to finish loading I used the method:   

    performSelectorOnMainThread:@selector(getBooks) withObject:nil waitUntilDone:YES  
However, when I run this the program continues executing although I set waitUntilDone to YES. I was under the impression that waitUntilDone would wait on the selector until it has finished executing. Can anyone explain what the possible issue could be? Thanks for any help.  