title: can't show the scrollview indicator in a scrollview
body: <p>This is my ViewController:</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
      self.imageView.image = self.image;
      self.scrollView.contentSize = self.imageView.image.size;
      self.imageView.frame = CGRectMake(0, 0, self.imageView.image.size.width, self.imageView.image.size.height);   
      self.title = [self.photo objectForKey:FLICKR_PHOTO_TITLE];
      self.scrollView.delegate = self;
  }
  
  - (void)viewDidAppear:(BOOL)animated
  {
      [self.scrollView flashScrollIndicators];
      self.scrollView.showsHorizontalScrollIndicator = YES;
  }
  </code></pre>
  
  <p>But it didn't show anything. 
  I already checked out several same questions in here and tried all the possible solutions, but none worked.</p>