UICollectionViewFlowLayout has cached frame mismatch
This is likely occurring because the flow layout subclass MyLineLayout is modifying attributes returned by UICollectionViewFlowLayout without copying them
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
NSArray *original = [super layoutAttributesForElementsInRect:rect];
NSArray *array = [[NSArray alloc] initWithArray:original copyItems:YES];
对array进行修改就可以了，不要对original修改
这样就不会报这个警告了