IGListUpdatingDelegate
@protocol IGListUpdatingDelegate
Implement this protocol in order to handle both section and row based update events. Implementation should forward or coalesce these events to a backing store or collection.
-
Asks the delegate for the pointer functions for looking up an object in a collection.
@discussion Since the updating delegate is responsible for transitioning between object sets, it becomes the
source of truth
for how objects and their corresponding section controllers are mapped. This allows the updater to control if objects are looked up by pointer, or more traditionally, with hash/isEqual.For behavior similar to NSDictionary, simply return +[NSPointerFunctions pointerFunctionsWithOptions:NSPointerFunctionsObjectPersonality].
Declaration
Objective-C
- (nonnull NSPointerFunctions *)objectLookupPointerFunctions;
Swift
func objectLookupPointerFunctions() -> Any!
Return Value
Pointer functions for looking up an object in a collection.
-
Tells the delegate to perform a section transition from an old array of objects to a new one.
@discussion Implementations determine how to transition between objects. You can perform a diff on the objects, reload each section, or simply call -reloadData on the collection view. In the end, the collection view must be setup with a section for each object in the toObjects array.
The
objectUpdateBlock
block should be called prior to making any UICollectionView updates, passing in thetoObjects
that the updater is applying.Declaration
Objective-C
- (void) performUpdateWithCollectionView:(nonnull UICollectionView *)collectionView fromObjects: (nullable NSArray<id<IGListDiffable>> *)fromObjects toObjects: (nullable NSArray<id<IGListDiffable>> *)toObjects animated:(BOOL)animated objectTransitionBlock: (nonnull IGListObjectTransitionBlock)objectTransitionBlock completion:(nullable IGListUpdatingCompletion)completion;
Swift
func performUpdate(withCollectionView collectionView: Any!, fromObjects: Any!, toObjects: Any!, animated: Any!, objectTransitionBlock: IGListObjectTransitionBlock!, completion: Any!)
Parameters
collectionView
The collection view to perform the transition on.
fromObjects
The previous objects in the collection view. Objects must conform to IGListDiffable.
toObjects
The new objects in collection view. Objects must conform to IGListDiffable.
animated
A flag indicating if the transition should be animated.
objectTransitionBlock
A block that must be called when the adapter applies changes to the collection view.
completion
A completion block to execute when the update is finished.
-
Tells the delegate to perform item inserts at the given index paths.
Declaration
Objective-C
- (void)insertItemsIntoCollectionView:(nonnull UICollectionView *)collectionView indexPaths: (nonnull NSArray<NSIndexPath *> *)indexPaths;
Swift
func insertItems(intoCollectionView collectionView: Any!, indexPaths: Any!)
Parameters
collectionView
The collection view to perform the transition on.
indexPaths
The index paths to insert items into.
-
Tells the delegate to perform item deletes at the given index paths.
Declaration
Objective-C
- (void)deleteItemsFromCollectionView:(nonnull UICollectionView *)collectionView indexPaths: (nonnull NSArray<NSIndexPath *> *)indexPaths;
Swift
func deleteItems(fromCollectionView collectionView: Any!, indexPaths: Any!)
Parameters
collectionView
The collection view to perform the transition on.
indexPaths
The index paths to delete items from.
-
Tells the delegate to perform item reloads at the given index paths.
Declaration
Objective-C
- (void)reloadItemsInCollectionView:(nonnull UICollectionView *)collectionView indexPaths: (nonnull NSArray<NSIndexPath *> *)indexPaths;
Swift
func reloadItems(inCollectionView collectionView: Any!, indexPaths: Any!)
Parameters
collectionView
The collection view to perform the transition on.
indexPaths
The index paths of items to reload.
-
Completely reload data in the collection.
Declaration
Objective-C
- (void) reloadDataWithCollectionView:(nonnull UICollectionView *)collectionView reloadUpdateBlock:(nonnull IGListReloadUpdateBlock)reloadUpdateBlock completion:(nullable IGListUpdatingCompletion)completion;
Swift
func reloadData(withCollectionView collectionView: Any!, reloadUpdate reloadUpdateBlock: IGListReloadUpdateBlock!, completion: Any!)
Parameters
collectionView
The collection view to reload.
reloadUpdateBlock
A block that must be called when the adapter reloads the collection view.
completion
A completion block to execute when the reload is finished.
-
Completely reload each section in the collection view.
Declaration
Objective-C
- (void)reloadCollectionView:(nonnull UICollectionView *)collectionView sections:(nonnull NSIndexSet *)sections;
Swift
func reloadCollectionView(_ collectionView: Any!, sections: Any!)
Parameters
collectionView
The collection view to reload.
sections
The sections to reload.
-
Perform an item update block in the collection view.
Declaration
Objective-C
- (void) performUpdateWithCollectionView:(nonnull UICollectionView *)collectionView animated:(BOOL)animated itemUpdates:(nonnull IGListItemUpdateBlock)itemUpdates completion:(nullable IGListUpdatingCompletion)completion;
Swift
func performUpdate(withCollectionView collectionView: Any!, animated: Any!, itemUpdates: IGListItemUpdateBlock!, completion: Any!)
Parameters
collectionView
The collection view to update.
animated
A flag indicating if the transition should be animated.
itemUpdates
A block containing all of the updates.
completion
A completion block to execute when the update is finished.