第9月第7天 uicollectionview

/**
The margins used to lay out content in the section controller.

@see `-[UICollectionViewFlowLayout sectionInset]`.
*/
open var inset: UIEdgeInsets

/**
The minimum spacing to use between rows of items.

@see `-[UICollectionViewFlowLayout minimumLineSpacing]`.
*/
open var minimumLineSpacing: CGFloat

/**
The minimum spacing to use between items in the same row.

@see `-[UICollectionViewFlowLayout minimumInteritemSpacing]`.
*/
open var minimumInteritemSpacing: CGFloat

/**
Asks the SupplementaryViewSource for a configured supplementary view for the specified kind and index.

@param elementKind The kind of supplementary view being requested
@param index The index for the supplementary veiw being requested.

@note This is your opportunity to do any supplementary view setup and configuration.

@warning You should never allocate new views in this method. Instead deque a view from the `IGListCollectionContext`.
*/
@available(iOS 6.0, *)
public func viewForSupplementaryElement(ofKind elementKind: String, at index: Int) -> UICollectionReusableView

/**
Asks the SupplementaryViewSource for the size of a supplementary view for the given kind and index path.

@param elementKind The kind of supplementary view.
@param index The index of the requested view.

@return The size for the supplementary view.
*/
public func sizeForSupplementaryView(ofKind elementKind: String, at index: Int) -> CGSize