UIActivityIndicatorView*activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(100, 100, 60, 60)];
// [self.view addSubview:activityIndicator];
// activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleGray;
// [activityIndicator startAnimating];
頂部菊花視圖
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
