I have try this and this is working... Please check frame of activityView... because its y is 500...
UIActionSheet *actionSheet = [[UIActionSheet alloc]
initWithTitle:nil
delegate:nil
cancelButtonTitle:@"Test"
destructiveButtonTitle:@"Test"
otherButtonTitles:nil];
[actionSheet showInView:self.view];
UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityView.frame = CGRectMake(100, 5, 15, 15);
[activityView startAnimating];
[actionSheet addSubview:activityView];
activityView.backgroundColor = [UIColor redColor];
actionSheet.backgroundColor = [UIColor greenColor];