在哪里使用uiActivityIndicatorView?

我已经把代码写进去了 -(void)loadView{ } 使用nsurl从Internet获取图像。但在加载图像之前,我需要显示旋转器( UIActivityIndicatorView )

#import "ImageFromWebViewController.h"
#define USE_TEST_SERVER 1
@implementation ImageFromWebViewController
+(NSString *)fileName 
{
#if USE_TEST_SERVER 
    return @"http://happyhyderabad.files.wordpress.com/2009/04/anushka4.jpg";
#else
    return @"http://nutritionresearchcenter.org/healthnews/wp-content/uploads/2008/07/johnny_depp.jpg";
#endif
}

- (void)loadView {
    NSString *urlString = [ImageFromWebViewController fileName];
    NSURL *url = [NSURL URLWithString:urlString];
    UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
    imageView = [[UIImageView alloc] initWithImage:image];
    contentView = [[UIScrollView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
    [contentView setContentSize:[image size]];
    [contentView addSubview:imageView];
    [imageView setUserInteractionEnabled:NO];
    self.view = contentView;
}

- (void)didReceiveMemoryWarning {
        [super didReceiveMemoryWarning];
        }

- (void)dealloc {
    [imageView release];
    [contentView release];
    [super dealloc];
}
@end

在 viewDidLoad 我写代码是为了 活动指示器视图 但是自旋体在加载图像后启动,并且没有停止。

我应该在哪里编写微调器的代码?