UICollectionView cell高度自适应

- (UICollectionViewLayoutAttributes*)preferredLayoutAttributesFittingAttributes:(UICollectionViewLayoutAttributes*)layoutAttributes {

    [self setNeedsLayout];

    [self layoutIfNeeded];

    CGSizesize = [self.contentViewsystemLayoutSizeFittingSize:layoutAttributes.size];

    CGRectcellFrame = layoutAttributes.frame;

    cellFrame.size.height= size.height;

    layoutAttributes.frame= cellFrame;

    returnlayoutAttributes;

}