Question

I want to implement a scroll view which looks like the stock ticker. It can respond slide or tap gesture.

How can I implement this? Please advise me. Thank you!

Answer 1

Conceptually I’d setup an container UIScrollView with the contents of the scrolling area as subviews. To simulate a circular scroll I’d keep an array of the subviews. I’d add a view just off screen at the starting edge, and take away a view just off screen at ending edge.

UIScrollViewDelegate methods will be called when a person starts or stops dragging the view, which you can use to start and stop the animated scrolling. Other methods in this protocol can be used to reset the contents of the scrollview when the edge is reached, so more views can be added as needed.

I’d probably use a CADisplayLink to manually manage the animations. The method given to the CADisplayLink would update the scroll and manage adding and subtracting views to the edges. It would also stop scrolling based on a flag set by the UIScrollViewDelegate methods when the person is dragging the scroll.