?_activityView = [[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];

?_activityView.center = self.view.center;

?_activityView.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;

?_activityView.hidesWhenStopped = YES;

?_activityView.color = [UIColor greenColor];

?[self.view addSubview:_activityView];

在需要開始的地方調(diào)用：

?[_activityView startAnimating];

在需要結(jié)束的地方調(diào)用：

[_activityView stopAnimating];