ASCollectionView Class Reference

Inherits from	UICollectionView
Declared in	ASCollectionView.h

Overview

Asynchronous UICollectionView with Intelligent Preloading capabilities.

ASCollectionView is a true subclass of UICollectionView, meaning it is pointer-compatible with code that currently uses UICollectionView.

The main difference is that asyncDataSource expects -nodeForItemAtIndexPath, an ASCellNode, and the sizeForItemAtIndexPath: method is eliminated (as are the performance problems caused by it). This is made possible because ASCellNodes can calculate their own size, and preload ahead of time.

Note: ASCollectionNode is strongly recommended over ASCollectionView. This class exists for adoption convenience.

`asyncDelegate`

The object that acts as the asynchronous delegate of the collection view

@property (nonatomic, weak) id<ASCollectionDelegate> asyncDelegate

Discussion

The delegate must adopt the ASCollectionDelegate protocol. The collection view maintains a weak reference to the delegate object.

The delegate object is responsible for providing size constraints for nodes and indicating whether batch fetching should begin.

Declared In

ASCollectionView.h

`asyncDataSource`

The object that acts as the asynchronous data source of the collection view

@property (nonatomic, weak) id<ASCollectionDataSource> asyncDataSource

Discussion

The datasource must adopt the ASCollectionDataSource protocol. The collection view maintains a weak reference to the datasource object.

The datasource object is responsible for providing nodes or node creation blocks to the collection view.

Declared In

ASCollectionView.h

`collectionNode`

Returns the corresponding ASCollectionNode

@property (nonatomic, weak, readonly) ASCollectionNode *collectionNode

Return Value

collectionNode The corresponding ASCollectionNode, if one exists.

Declared In

ASCollectionView.h

`leadingScreensForBatching`

The number of screens left to scroll before the delegate -collectionView:beginBatchFetchingWithContext: is called.

@property (nonatomic, assign) CGFloat leadingScreensForBatching

Discussion

Defaults to two screenfuls.

Declared In

ASCollectionView.h

`layoutInspector`

Optional introspection object for the collection view’s layout.

@property (nonatomic, weak) id<ASCollectionViewLayoutInspecting> layoutInspector

Discussion

Since supplementary and decoration views are controlled by the collection view’s layout, this object is used as a bridge to provide information to the internal data controller about the existence of these views and their associated index paths. For collection views using UICollectionViewFlowLayout, a default inspector implementation ASCollectionViewFlowLayoutInspector is created and set on this property by default. Custom collection view layout subclasses will need to provide their own implementation of an inspector object for their supplementary views to be compatible with ASCollectionView’s supplementary node support.

Declared In

ASCollectionView.h

`– nodeForItemAtIndexPath:`

Retrieves the node for the item at the given index path.

- (nullable ASCellNode *)nodeForItemAtIndexPath:(NSIndexPath *)indexPath

Parameters

`indexPath`	The index path of the requested node.

Return Value

The node at the given index path, or @c nil if no item exists at the specified path.

Declared In

ASCollectionView.h

`– supplementaryNodeForElementKind:atIndexPath:`

Similar to -supplementaryViewForElementKind:atIndexPath:

- (nullable ASCellNode *)supplementaryNodeForElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath

Parameters

`elementKind`	The kind of supplementary node to locate.
`indexPath`	The index path of the requested supplementary node.

Return Value

The specified supplementary node or @c nil.

Declared In

ASCollectionView.h

`– contextForSection:`

Retrieves the context object for the given section, as provided by the data source in the @c collectionNode:contextForSection: method. This method must be called on the main thread.

- (nullable id<ASSectionContext>)contextForSection:(NSInteger)section

Parameters

`section`	The section to get the context for.

Return Value

The context object, or @c nil if no context was provided.

Declared In

ASCollectionView.h

`scrollDirection`

Determines collection view’s current scroll direction. Supports 2-axis collection views.

@property (nonatomic, readonly) ASScrollDirection scrollDirection

Return Value

a bitmask of ASScrollDirection values.

Declared In

ASCollectionView.h

`scrollableDirections`

Determines collection view’s scrollable directions.

@property (nonatomic, readonly) ASScrollDirection scrollableDirections

Return Value

a bitmask of ASScrollDirection values.

Declared In

ASCollectionView.h

`zeroContentInsets`

Forces the .contentInset to be UIEdgeInsetsZero.

@property (nonatomic) BOOL zeroContentInsets

Discussion

By default, UIKit sets the top inset to the navigation bar height, even for horizontally scrolling views. This can only be disabled by setting a property on the containing UIViewController, automaticallyAdjustsScrollViewInsets, which may not be accessible. ASPagerNode uses this to ensure its flow layout behaves predictably and does not log undefined layout warnings.

Declared In

ASCollectionView.h