CODEWITHSUNDEEP
iosswiftuiscrollview
marek.pivovarnik
marek.pivovarnik

Reputation: 155

Very slow deceleration in UIScrollView just in certain cases

I am struggling with aligning a screen to a certain Views inside a UIScrollView. I would like to have same behaviour as paging (same fast and smooth deceleration) but with alignment to a custom views instead of stoping on multiples of the scroll view’s bounds. I have implemented delegate method scrollViewWillEndDragging(_:withVelocity:targetContentOffset:) in order to define my own scroll view’s bounds location. I have also set decelerationRate to UIScrollViewDecelerationRateFast.

It work mostly as desired except the cases when alignment animation is very slow. To be more precise, sometimes, after the dragging is finished, the scrolling animation decelerates to final point very slowly. It finally reach the correct point but after a longer while. I am not able to track down the cases when it happens. I am able to say that everything works fine when final velocity of dragging is zero. Thus, it happens only in some cases when dragging is finished with nonzero velocity.

I wonder if somebody had same problem since I wasn't able to google anything useful. Can you help me please?

Upvotes: 3

Views: 921

Answers (1)

marek.pivovarnik
marek.pivovarnik

Reputation: 155

I have solved this problem by implementing delegate methods scrollViewDidEndDragging and scrollViewWillBeginDecelerating. Then by using information from scroll view’s pan gesture I found out about translation and I determined final scroll view’s bounds location using setContentOffset method on scroll view.

Upvotes: 1

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