创造iPhone等待图标

.h: 　　UIActivityIndicatorView* progressView; .m: 　　// show the waiting symbol 　　progressView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; 　　[progressView setCenter:CGPointMake(160.0f, 240.0f)]; 　　[progressView startAnimating]; 　　[self.view addSubview:progressView]; 　　// dismiss the waiting symbol 　　[progressView removeFromSuperview]; 　　[progressView stopAnimating]; 　　[progressView release];