UIActivityIndicatorView

    UIActivityIndicatorView *activityTest= [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(220, 140, 50, 50)];//指定進度輪的大小
    [activityTest startAnimating];
    [activityTest setCenter:CGPointMake(160, 208)];
    activityTest.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge; //設置進度輪顯示類型
    
    [self.view addSubview:activityTest];
    [activityTest release];
    
//    停止調用[activityTest stopAnimating];