UICollectionView doesn't bounce when datasource has only 1 item
UICollectionView has the properties alwaysBounceHorizontal and alwaysBounceVertical. Setting the horizontal to YES did the trick.
Thanks for @VaporwareWolf ,the answer is correct. I want to add a supplement that:
DO NOT forget setting the
bouncesproperty toYESat the same time（through storyboard or your code）.