报错提示：
*** Assertion failure in -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:viewCategory:], /SourceCache/UIKit_Sim/UIKit-3318.16.14/UICollectionView.m:3307
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'invalid nib registered for identifier (SXDealCellID) - nib must contain exactly one top level object which must be a UICollectionReusableView instance'
解决方案：
在自定义xib时，额外多了一个控件在另外的区域，把此控件删掉即可。