iPhone UIActivityIndicatorView not starting or stopping

Question

When I call startAnimating on a UIActivityIndicatorView, it doesn\'t start. Why is this?

[This is a blog-style self-answered question. The solution below works for

Answer 1

All UI elements require to be on main thread

[self performSelectorOnMainThread:@selector(startIndicator) withObject:nil waitUntilDone:NO];

then:

-(void)startIndicator{
    [activityIndicator startAnimating];
}