UIActivityIndicatorView *indicator = nil;
indicator = (UIActivityIndicatorView *)[self.view viewWithTag:103];
if (indicator == nil) {
//初始化:
UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0, 0, 80, 80)];
indicator.tag = 103;
//设置显示样式,见UIActivityIndicatorViewStyle的定义
indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
//设置背景色
indicator.backgroundColor = [UIColor blackColor];
//设置背景透明
indicator.alpha = 0.5;
//设置背景为圆角矩形
indicator.layer.cornerRadius = 6;
indicator.layer.masksToBounds = YES;
//设置显示位置
[indicator setCenter:CGPointMake(self.view.frame.size.width / 2.0, self.view.frame.size.height / 2.0)];
//开始显示Loading动画
[indicator startAnimating];
[self.view addSubview:indicator];
[indicator release];
}
//开始显示Loading动画
[indicator startAnimating];
// 停止动画
UIActivityIndicatorView *indicator = (UIActivityIndicatorView *)[self.view viewWithTag:103];
//停止显示Loading动画
[indicator stopAnimating];