Created
October 23, 2017 11:26
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A DataProvider which can be used by different dataSources at the same time
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| final public class NameDifferentDataProvider<Element>: DataProviding { | |
| /// Closure which gets called, when a data inside the provider changes and those changes should be propagated to the datasource. | |
| /// **Warning:** Only set this when you are updating the datasource. | |
| public var whenDataProviderChanged: ProcessUpdatesCallback<Element>? { | |
| get { | |
| return realWhenDataProviderChanged | |
| } | |
| set { | |
| newValue.map { didChanges.append($0) } | |
| } | |
| } | |
| private var didChanges: [ProcessUpdatesCallback<Element>] = [] | |
| private var realWhenDataProviderChanged: ProcessUpdatesCallback<Element>? | |
| private let objectAtIndexPath: (_ atIndexPath: IndexPath) -> Element | |
| private let numberOfItems: (_ inSextion: Int) -> Int | |
| private let numberOfSectionsCallback: () -> Int | |
| private let prefetchItemsAtIndexPaths: ([IndexPath]) -> Void | |
| private let cancelPrefetchingForItemsAtIndexPaths: ([IndexPath]) -> Void | |
| private let getSectionIndexTitles: () -> [String]? | |
| private let getHeaderTitles: () -> [String]? | |
| public var sectionIndexTitles: [String]? { | |
| return getSectionIndexTitles() | |
| } | |
| public var headerTitles: [String]? { | |
| return getHeaderTitles() | |
| } | |
| public init<DataProvider: DataProviding>(_ dataProvider: DataProvider) where Element == DataProvider.Element { | |
| objectAtIndexPath = { indexPath in | |
| return dataProvider.object(at: indexPath) | |
| } | |
| numberOfItems = { section in | |
| return dataProvider.numberOfItems(inSection: section) | |
| } | |
| numberOfSectionsCallback = { | |
| return dataProvider.numberOfSections() | |
| } | |
| prefetchItemsAtIndexPaths = { indexPaths in | |
| dataProvider.prefetchItems(at: indexPaths) | |
| } | |
| cancelPrefetchingForItemsAtIndexPaths = { indexPaths in | |
| dataProvider.cancelPrefetchingForItems(at: indexPaths) | |
| } | |
| getSectionIndexTitles = { | |
| return dataProvider.sectionIndexTitles | |
| } | |
| getHeaderTitles = { | |
| return dataProvider.headerTitles | |
| } | |
| realWhenDataProviderChanged = { [weak self] updates in | |
| guard let strongSelf = self else { return } | |
| for handler in strongSelf.didChanges { | |
| handler(updates) | |
| } | |
| } | |
| dataProvider.whenDataProviderChanged = realWhenDataProviderChanged | |
| } | |
| public func object(at indexPath: IndexPath) -> Element { | |
| return objectAtIndexPath(indexPath) | |
| } | |
| public func numberOfItems(inSection section: Int) -> Int { | |
| return numberOfItems(section) | |
| } | |
| public func numberOfSections() -> Int { | |
| return numberOfSectionsCallback() | |
| } | |
| public func prefetchItems(at indexPaths: [IndexPath]) { | |
| prefetchItemsAtIndexPaths(indexPaths) | |
| } | |
| public func cancelPrefetchingForItems(at indexPaths: [IndexPath]) { | |
| cancelPrefetchingForItemsAtIndexPaths(indexPaths) | |
| } | |
| } |
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