问题
I have a vertically-scrolling scroll view that has a single subview. This subview has a couple of collection views. I want them to scroll horizontally. It doesn't work because they are inside the scroll view. The problem is that the pan/scrolling gesture is working just for the scroll view and it doesn't propagate to the collection views. I just see the scroll view scrolling. There is the same problem with tapping on a collection cell. This event just doesn't happen.
I already tried adding the gestures manually but I am not able to scroll the collection views.
How can I propagate all the gestures ?
Thank you !
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来源：https://stackoverflow.com/questions/43634939/uicollectionview-inside-uiscrollview-not-scrolling