Question

In the Appstore screen shots section, just wondering how would someone implement the way Apple automatically scrolls down right at the screen shot edges when a user starts paging the screenshots horizontally?

Did they use animation? How would you do it?

Thanks!

Answer 1

They probably use the UIScrollView method:

- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated

or the UIScrollView method:

- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated

When the horizontal scroll view’s delegate method

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

gets called, figure out the rect or point you want, and then do:

[theVerticalScrollView scrollRectToVisible:theRectYouWant animated:YES];

or

[theVerticalScrollView setContentOffset:thePointYouWant animated:YES];