// // UICollectionViewWaterfallLayout.h // // Created by Nelson on 12/11/19. // Copyright (c) 2012 Nelson Tai. All rights reserved. // #import /** * Enumerated structure to define direction in which items can be rendered. */ typedef NS_ENUM (NSUInteger, CHTCollectionViewWaterfallLayoutItemRenderDirection) { CHTCollectionViewWaterfallLayoutItemRenderDirectionShortestFirst, CHTCollectionViewWaterfallLayoutItemRenderDirectionLeftToRight, CHTCollectionViewWaterfallLayoutItemRenderDirectionRightToLeft }; /** * Constants that specify the types of supplementary views that can be presented using a waterfall layout. */ /// A supplementary view that identifies the header for a given section. extern NSString *const CHTCollectionElementKindSectionHeader; /// A supplementary view that identifies the footer for a given section. extern NSString *const CHTCollectionElementKindSectionFooter; #pragma mark - CHTCollectionViewDelegateWaterfallLayout @class CHTCollectionViewWaterfallLayout; /** * The CHTCollectionViewDelegateWaterfallLayout protocol defines methods that let you coordinate with a * CHTCollectionViewWaterfallLayout object to implement a waterfall-based layout. * The methods of this protocol define the size of items. * * The waterfall layout object expects the collection view’s delegate object to adopt this protocol. * Therefore, implement this protocol on object assigned to your collection view’s delegate property. */ @protocol CHTCollectionViewDelegateWaterfallLayout @required /** * Asks the delegate for the size of the specified item’s cell. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param indexPath * The index path of the item. * * @return * The original size of the specified item. Both width and height must be greater than 0. */ - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath; @optional /** * Asks the delegate for the column count in a section * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The section. * * @return * The original column count for that section. Must be greater than 0. */ - (NSInteger)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout columnCountForSection:(NSInteger)section; /** * Asks the delegate for the height of the header view in the specified section. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose header size is being requested. * * @return * The height of the header. If you return 0, no header is added. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its headerHeight property to set the size of the header. * * @see * headerHeight */ - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout heightForHeaderInSection:(NSInteger)section; /** * Asks the delegate for the height of the footer view in the specified section. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose header size is being requested. * * @return * The height of the footer. If you return 0, no footer is added. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its footerHeight property to set the size of the footer. * * @see * footerHeight */ - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout heightForFooterInSection:(NSInteger)section; /** * Asks the delegate for the insets in the specified section. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose insets are being requested. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its sectionInset property. * * @return * The insets for the section. */ - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section; /** * Asks the delegate for the header insets in the specified section. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose header insets are being requested. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its headerInset property. * * @return * The headerInsets for the section. */ - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForHeaderInSection:(NSInteger)section; /** * Asks the delegate for the footer insets in the specified section. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose footer insets are being requested. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its footerInset property. * * @return * The footerInsets for the section. */ - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForFooterInSection:(NSInteger)section; /** * Asks the delegate for the minimum spacing between two items in the same column * in the specified section. If this method is not implemented, the * minimumInteritemSpacing property is used for all sections. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose minimum interitem spacing is being requested. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its minimumInteritemSpacing property to determine the amount of space between items in the same column. * * @return * The minimum interitem spacing. */ - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section; /** * Asks the delegate for the minimum spacing between colums in a secified section. If this method is not implemented, the * minimumColumnSpacing property is used for all sections. * * @param collectionView * The collection view object displaying the waterfall layout. * @param collectionViewLayout * The layout object requesting the information. * @param section * The index of the section whose minimum interitem spacing is being requested. * * @discussion * If you do not implement this method, the waterfall layout uses the value in its minimumColumnSpacing property to determine the amount of space between columns in each section. * * @return * The minimum spacing between each column. */ - (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumColumnSpacingForSectionAtIndex:(NSInteger)section; @end #pragma mark - CHTCollectionViewWaterfallLayout /** * The CHTCollectionViewWaterfallLayout class is a concrete layout object that organizes items into waterfall-based grids * with optional header and footer views for each section. * * A waterfall layout works with the collection view’s delegate object to determine the size of items, headers, and footers * in each section. That delegate object must conform to the `CHTCollectionViewDelegateWaterfallLayout` protocol. * * Each section in a waterfall layout can have its own custom header and footer. To configure the header or footer for a view, * you must configure the height of the header or footer to be non zero. You can do this by implementing the appropriate delegate * methods or by assigning appropriate values to the `headerHeight` and `footerHeight` properties. * If the header or footer height is 0, the corresponding view is not added to the collection view. * * @note CHTCollectionViewWaterfallLayout doesn't support decoration view, and it supports vertical scrolling direction only. */ @interface CHTCollectionViewWaterfallLayout : UICollectionViewLayout @property(nonatomic,copy)NSArray*lockingHeadSections;//锁定区头的索引数组NSSting类型 /** * @brief How many columns for this layout. * @discussion Default: 2 */ @property (nonatomic, assign) NSInteger columnCount; /** * @brief The minimum spacing to use between successive columns. * @discussion Default: 10.0 */ @property (nonatomic, assign) CGFloat minimumColumnSpacing; /** * @brief The minimum spacing to use between items in the same column. * @discussion Default: 10.0 * @note This spacing is not applied to the space between header and columns or between columns and footer. */ @property (nonatomic, assign) CGFloat minimumInteritemSpacing; /** * @brief Height for section header * @discussion * If your collectionView's delegate doesn't implement `collectionView:layout:heightForHeaderInSection:`, * then this value will be used. * * Default: 0 */ @property (nonatomic, assign) CGFloat headerHeight; /** * @brief Height for section footer * @discussion * If your collectionView's delegate doesn't implement `collectionView:layout:heightForFooterInSection:`, * then this value will be used. * * Default: 0 */ @property (nonatomic, assign) CGFloat footerHeight; /** * @brief The margins that are used to lay out the header for each section. * @discussion * These insets are applied to the headers in each section. * They represent the distance between the top of the collection view and the top of the content items * They also indicate the spacing on either side of the header. They do not affect the size of the headers or footers themselves. * * Default: UIEdgeInsetsZero */ @property (nonatomic, assign) UIEdgeInsets headerInset; /** * @brief The margins that are used to lay out the footer for each section. * @discussion * These insets are applied to the footers in each section. * They represent the distance between the top of the collection view and the top of the content items * They also indicate the spacing on either side of the footer. They do not affect the size of the headers or footers themselves. * * Default: UIEdgeInsetsZero */ @property (nonatomic, assign) UIEdgeInsets footerInset; /** * @brief The margins that are used to lay out content in each section. * @discussion * Section insets are margins applied only to the items in the section. * They represent the distance between the header view and the columns and between the columns and the footer view. * They also indicate the spacing on either side of columns. They do not affect the size of the headers or footers themselves. * * Default: UIEdgeInsetsZero */ @property (nonatomic, assign) UIEdgeInsets sectionInset; /** * @brief The direction in which items will be rendered in subsequent rows. * @discussion * The direction in which each item is rendered. This could be left to right (CHTCollectionViewWaterfallLayoutItemRenderDirectionLeftToRight), right to left (CHTCollectionViewWaterfallLayoutItemRenderDirectionRightToLeft), or shortest column fills first (CHTCollectionViewWaterfallLayoutItemRenderDirectionShortestFirst). * * Default: CHTCollectionViewWaterfallLayoutItemRenderDirectionShortestFirst */ @property (nonatomic, assign) CHTCollectionViewWaterfallLayoutItemRenderDirection itemRenderDirection; /** * @brief The minimum height of the collection view's content. * @discussion * The minimum height of the collection view's content. This could be used to allow hidden headers with no content. * * Default: 0.f */ @property (nonatomic, assign) CGFloat minimumContentHeight; /** * @brief The calculated width of an item in the specified section. * @discussion * The width of an item is calculated based on number of columns, the collection view width, and the horizontal insets for that section. */ - (CGFloat)itemWidthInSectionAtIndex:(NSInteger)section; @end