支持头部视图拓展后，Cell高度出现不太准确的问题

[ETmanwenhan]

• (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect { [self initCellYArray]; NSMutableArray *array = [NSMutableArray array]; for (NSInteger i = 0; i < _indexCountBySectionForHeight.count; i++) {

    //SectionHeader
    UICollectionViewLayoutAttributes *attributesHeader = [self layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader atIndexPath:[NSIndexPath indexPathForRow:0 inSection:i]];
    [array addObject:attributesHeader];
  
    for (NSInteger j = 0; j < _indexCountBySectionForHeight[i].count; j++) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForItem:j inSection:i];
        UICollectionViewLayoutAttributes *attributes = [self layoutAttributesForItemAtIndexPath:indexPath];
        [array addObject:attributes];
  
    }
  

  } return array; }

• (UICollectionViewLayoutAttributes *)layoutAttributesForSupplementaryViewOfKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath { CGFloat height = [self maxCellYArrayWithArray:_cellYArray]; [self resetCellYArray:height]; UICollectionViewLayoutAttributes *attribute = [UICollectionViewLayoutAttributes layoutAttributesForSupplementaryViewOfKind:elementKind withIndexPath:indexPath]; attribute.frame = CGRectMake(0, height, self.headerReferenceSize.width, self.headerReferenceSize.height); return attribute; }