iOS 之 系统自带菊花视图

UIActivityIndicatorView*activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(100, 100, 60, 60)];
//    [self.view addSubview:activityIndicator];
//    activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;
//    [activityIndicator startAnimating];

顶部菊花视图

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;