Backward Scroll - ios

Question

Hi I have 10 images in UIScrollview now i can scroll forward like from 1 to 2,3,4,etc but in my project i need to scroll images backward direction also like from 1 to 10 to left hand side
this is my code
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
CGFloat pageWidth = cardsScrollView.frame.size.width;
NSUInteger page = floor((self.cardsScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
if(page + 1 == [flashCardArry count]){
for (NSUInteger i = 0; i < [flashCardArry count]; ++i) {
int nElements = [flashCardArry count] - i;
int n = (arc4random() % nElements) + i;
[flashCardArry exchangeObjectAtIndex:i withObjectAtIndex:n];
}
[self.cardsScrollView scrollRectToVisible:CGRectMake(self.cardsScrollView.frame.size.width * 0 , 0, self.cardsScrollView.frame.size.width, self.cardsScrollView.frame.size.height) animated:NO];
}
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
CGFloat pageWidth = cardsScrollView.frame.size.width;
NSUInteger page = floor((self.cardsScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;

Answer 1

You can simply do that by adding the imageViews from 10 to 1 on your scrollView and then you have se the contentOffset of you scrollview to point to the last image which is image 1.
So user wont be able to scroll right at first, he can scroll to left for next images.

Answer 2

So. In case if you want cyclic scrollview you would need next things:
1) hide scrollView indicators
scrl.showsHorizontalScrollIndicator = NO;
scrl.showsVerticalScrollIndicator = NO;
2) Add one item to beginning of the scroll view, and one item at the end
[5'] | [0][1][2][3][4][5] | [0']
| --- full_size--- |
3) Once user scrolls to 5' item we updating content offset by adding full_size
4) Once user scrolls to 0' item we updating content offset by subtracting full_size
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGPoint contentOffset = scrollView.contentOffset;
// First item
if (contentOffset.x < page_size) { // We are now faking last page
scrollView.contentOffset += full_size; // Jumping to actual last page
}
// Last item
if (contentOffset.x > full_size) { // We are now faking first page
scrollView.contentOffset -= full_size; // Jumping to actual first page
}
}
5) To decrease amount of jumps (especially on the borders), you can add more 2 or more fake items from both side