iPhone UIScrollView - how to get an image title.

Question

Hi,

I'm ATTEMPTING to learn UIScrollview using Apple's Docs and their sample code http://developer.apple.com/iphone/library/samplecode/Scrolling/index.html but something SO simple is escaping me.

How do you tell what image is currently on the screen, so that if I selected one of the images in the horizontal scrolling view, how would I get the filename of the image, or even a pointer in the array, to then do something further with the image.

I thought with Page Control enable I might be able to find a page # and map it to the image. I thought about counting deceleration to count pages, but a flick no full enough will increment it and give a false number.

The last thing I could think of is to get contentOffSet and divide by image size which will give a 1, 2, 3 and I could point to the array (too tired to try tonight... thought I might ask before I waste a lot more time ;-) ).

Any other ideas? I thought their'd be a method somewhere that they use in the photo album app.

Thanks for your help! Maybe I'm just not understanding their code.

Paul

PS: Here's the code:

- (void)layoutScrollImages

{ UIImageView *view = nil; NSArray *subviews = [scrollView1 subviews];

// reposition all image subviews in a horizontal serial fashion
CGFloat curXLoc = 0;
for (view in subviews)
{
 if ([view isKindOfClass:[UIImageView class]] && view.tag > 0)
 {
  CGRect frame = view.frame;
  frame.origin = CGPointMake(curXLoc, 0);
  view.frame = frame;

  curXLoc += (kScrollObjWidth);
 }
}

// set the content size so it can be scrollable
[scrollView1 setContentSize:CGSizeMake((kNumImages * kScrollObjWidth), [scrollView1 bounds].size.height)];

}

• (void)viewDidLoad { self.view.backgroundColor = [UIColor viewFlipsideBackgroundColor];

  // 1. setup the scrollview for multiple images and add it to the view controller // // note: the following can be done in Interface Builder, but we show this in code for clarity [scrollView1 setBackgroundColor:[UIColor blackColor]]; [scrollView1 setCanCancelContentTouches:NO]; scrollView1.indicatorStyle = UIScrollViewIndicatorStyleWhite; scrollView1.clipsToBounds = YES; // default is NO, we want to restrict drawing within our scrollview scrollView1.scrollEnabled = YES;

  // pagingEnabled property default is NO, if set the scroller will stop or snap at each photo // if you want free-flowing scroll, don't set this property. scrollView1.pagingEnabled = YES;

  // load all the images from our bundle and add them to the scroll view //NSUInteger i; for (i = 1; i <= kNumImages; i++) { NSString *imageName = [NSString stringWithFormat:@"Card %d.png", i]; UIImage *image = [UIImage imageNamed:imageName]; UIImageView *imageView = [[UIImageView alloc] initWithImage:image];

  // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
  CGRect rect = imageView.frame;
  rect.size.height = kScrollObjHeight;
  rect.size.width = kScrollObjWidth;
  imageView.frame = rect;
  imageView.tag = i; // tag our images for later use when we place them in serial fashion
  [scrollView1 addSubview:imageView];
  [imageView release];
  

  }

  [self layoutScrollImages]; // now place the photos in serial layout within the scrollview

Answer 1

This was easy after a good sleep!

CGPoint p = scrollView1.contentOffset;
NSLog(@"x = %f, y = %f", p.x, p.y);

Now just divide by 320 (if horizontal and full screen image) and add 1 (because it starts at 0).

Hope this helps someone else!

Paul

Answer 2

This Really helped me a lot, thank you so very much!

Answer 3

Can you please tell me where exactly i can use this function