UIActivityIndicatorView

UIActivityIndicatorViewUIActivityIndicatorView * activity = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];//指定进度轮的大小

UIActivityIndicatorView * activity = [[UIActivityIndicatorViewalloc] initWithFrame:CGRectMake(0, 0, 30, 30)];//指定进度轮的大小 

    [activity setCenter:CGPointMake(160, 140)];//指定进度轮中心点

    [activitysetActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];//设置进度轮显示类型

    [self.view addSubview:activity];

//指示器停止

 [activity stopAnimating];

//指示器开始

[activity startAnimating];