UIWebView in multithread ViewController

Question

I have a UIWebView in a viewcontroller, which has two methods as below. The question is if I pop out(tap back on navigation bar) this controller before the second thread is

Answer 1

In general, you should cancel any background operations when the view that uses them is going away. As in:

- (void)viewWillDisappear:(BOOL)animated {
  [operationQueue cancelAllOperations];
  [super viewWillDisappear:animated;
}