IGListAdapterDataSource

Objective-C

@protocol IGListAdapterDataSource <NSObject>

Swift

@MainActor protocol ListAdapterDataSource : NSObjectProtocol

Implement this protocol to provide data to an IGListAdapter.

  • Asks the data source for the objects to display in the list.

    Declaration

    Objective-C

    - (nonnull NSArray<id<IGListDiffable>> *)objectsForListAdapter:
    (nonnull IGListAdapter *)listAdapter;

    Swift

    func objects(for listAdapter: IGListAdapter) -> [any ListDiffable]

    Parameters

    listAdapter

    The list adapter requesting this information.

    Return Value

    An array of objects for the list.

  • Asks the data source for a section controller for the specified object in the list.

    Note

    New section controllers should be initialized here for objects when asked. You may pass any other data to the section controller at this time.

    Section controllers are initialized for all objects whenever the IGListAdapter is created, updated, or reloaded. Section controllers are reused when objects are moved or updated. Maintaining the -[IGListDiffable diffIdentifier] guarantees this.

    Declaration

    Objective-C

    - (nonnull IGListSectionController *)listAdapter:
                                         (nonnull IGListAdapter *)listAdapter
                      sectionControllerForObject:(nonnull id)object;

    Swift

    func listAdapter(_ listAdapter: IGListAdapter, sectionControllerFor object: Any) -> IGListSectionController

    Parameters

    listAdapter

    The list adapter requesting this information.
    object

    An object in the list.

    Return Value

    A new section controller instance that can be displayed in the list.

  • Asks the data source for a view to use as the collection view background when the list is empty.

    Note

    This method is called every time the list adapter is updated. You are free to return new views every time, but for performance reasons you may want to retain the view and return it here. The infra is only responsible for adding the background view and maintaining its visibility.

    Declaration

    Objective-C

    - (nullable UIView *)emptyViewForListAdapter:
    (nonnull IGListAdapter *)listAdapter;

    Swift

    func emptyView(for listAdapter: IGListAdapter) -> UIView?

    Parameters

    listAdapter

    The list adapter requesting this information.

    Return Value

    A view to use as the collection view background, or nil if you don’t want a background view.