我已经实现UIActivity了指标并添加到ViewDidLoad.Method如下视图中:
UIActivityIndicatorView *act=[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
act.frame=CGRectMake(150, 240, 45, 45);
[act startAnimating];
[self.view addSubview:act];
但我无法查看在视图中旋转的微调器。谁能告诉我是什么问题?