Create:
spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[spinner setCenter:CGPointMake(kScreenWidth/2.0, kScreenHeight/2.0)]; // I do this because I'm in landscape mode
[self.view addSubview:spinner]; // spinner is not visible until started
Start:
[spinner startAnimating];
Stop:
[spinner stopAnimating];
When you're finally done, remove the spinner from the view and release.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…