How can I programmatically change the position of a UIScrollView based on another views change?

Question

I have a scrollView that I'd like to programmatically move based on the delta, or change of another scrollView. So if my first scrollView moves down 10px, I need to get that number, and adjust the second scrollView down 10px, and allow them to be in different positions.

The only other way I've gotten it to work (thanks to someone else's post on here) is with this code:

[scrollView setContentOffset:offset animated:NO];

But that just makes them have the same XY coordinates, which isn't what I'm looking for.

Thanks for your help!

score 0 · Accepted Answer · answered Jul 10 '11 at 03:08

0

Just use the delegate method

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

To determine the value of each content offset when scrolling starts. Then each time scrolling is updated you can tell how much it has changed by, and adjust the other scroll view. It's just math.

answered Jul 10 '11 at 03:08

jtbandes

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Hey that makes sense! Thank you! Is there an optimal of programmatically setting the scrollView's position? – Jarom Jul 10 '11 at 03:27
@Jarom See `scrollToRect` method of UIScrollView – Rog Jul 10 '11 at 03:30
@Jarom I think the best way is using contentOffset, like you did before. You just have to do the math first. – jtbandes Jul 10 '11 at 03:41

How can I programmatically change the position of a UIScrollView based on another views change?

1 Answers1