Files
CoreStore/Sources/DiffableDataSource.TableViewAdapter-UIKit.swift

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Swift

//
// DiffableDataSource.TableViewAdapter-UIKit.swift
// CoreStore
//
// Copyright © 2018 John Rommel Estropia
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
#if canImport(UIKit) && (os(iOS) || os(tvOS))
import UIKit
import CoreData
// MARK: - DiffableDataSource
extension DiffableDataSource {
// MARK: - TableViewAdapter
/**
The `DiffableDataSource.TableViewAdapterAdapter` serves as a `UITableViewDataSource` that handles `ListPublisher` snapshots for a `UITableView`. Subclasses of `DiffableDataSource.TableViewAdapter` may override some `UITableViewDataSource` methods as needed.
The `DiffableDataSource.TableViewAdapterAdapter` instance needs to be held on (retained) for as long as the `UITableView`'s lifecycle.
```
self.dataSource = DiffableDataSource.TableViewAdapter<Person>(
tableView: self.tableView,
dataStack: CoreStoreDefaults.dataStack,
cellProvider: { (tableView, indexPath, person) in
let cell = tableView.dequeueReusableCell(withIdentifier: "PersonCell") as! PersonCell
cell.setPerson(person)
return cell
}
)
```
The dataSource can then apply changes from a `ListPublisher` as shown:
```
listPublisher.addObserver(self) { [weak self] (listPublisher) in
self?.dataSource?.apply(
listPublisher.snapshot,
animatingDifferences: true
)
}
```
`DiffableDataSource.TableViewAdapter` fully handles the reload animations.
- SeeAlso: CoreStore's DiffableDataSource implementation is based on https://github.com/ra1028/DiffableDataSources
*/
open class TableViewAdapter<O: DynamicObject>: BaseAdapter<O, DefaultTableViewTarget<UITableView>>, UITableViewDataSource {
// MARK: Public
/**
Initializes the `DiffableDataSource.TableViewAdapter`. This instance needs to be held on (retained) for as long as the `UITableView`'s lifecycle.
```
self.dataSource = DiffableDataSource.TableViewAdapter<Person>(
tableView: self.tableView,
dataStack: CoreStoreDefaults.dataStack,
cellProvider: { (tableView, indexPath, person) in
let cell = tableView.dequeueReusableCell(withIdentifier: "PersonCell") as! PersonCell
cell.setPerson(person)
return cell
}
)
```
- parameter tableView: the `UITableView` to set the `dataSource` of. This instance is not retained by the `DiffableDataSource.TableViewAdapter`.
- parameter dataStack: the `DataStack` instance that the dataSource will fetch objects from
- parameter cellProvider: a closure that configures and returns the `UITableViewCell` for the object
*/
public init(
tableView: UITableView,
dataStack: DataStack,
cellProvider: @escaping (UITableView, IndexPath, O) -> UITableViewCell?
) {
self.cellProvider = cellProvider
super.init(target: .init(tableView), dataStack: dataStack)
tableView.dataSource = self
}
/**
The target `UITableView`
*/
public var tableView: UITableView? {
return self.target.base
}
// MARK: - UITableViewDataSource
@objc
@MainActor
public dynamic func numberOfSections(in tableView: UITableView) -> Int {
return self.numberOfSections()
}
@objc
@MainActor
public dynamic func tableView(
_ tableView: UITableView,
numberOfRowsInSection section: Int
) -> Int {
return self.numberOfItems(inSection: section) ?? 0
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
titleForHeaderInSection section: Int
) -> String? {
return self.sectionID(for: section)
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
titleForFooterInSection section: Int
) -> String? {
return nil
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
cellForRowAt indexPath: IndexPath
) -> UITableViewCell {
guard let objectID = self.itemID(for: indexPath) else {
Internals.abort("Object at \(Internals.typeName(IndexPath.self)) \(indexPath) already removed from list")
}
guard let object = self.dataStack.fetchExisting(objectID) as O? else {
Internals.abort("Object at \(Internals.typeName(IndexPath.self)) \(indexPath) has been deleted")
}
guard let cell = self.cellProvider(tableView, indexPath, object) else {
Internals.abort("\(Internals.typeName(UITableViewDataSource.self)) returned a `nil` cell for \(Internals.typeName(IndexPath.self)) \(indexPath)")
}
return cell
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
canEditRowAt indexPath: IndexPath
) -> Bool {
return true
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
editingStyleForRowAt indexPath: IndexPath
) -> UITableViewCell.EditingStyle {
return .delete
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
commit editingStyle: UITableViewCell.EditingStyle,
forRowAt indexPath: IndexPath
) {}
@objc
@MainActor
open dynamic func sectionIndexTitles(
for tableView: UITableView
) -> [String]? {
return nil
}
@objc
@MainActor
open dynamic func tableView(
_ tableView: UITableView,
sectionForSectionIndexTitle title: String,
at index: Int
) -> Int {
return index
}
// MARK: Private
@nonobjc
private let cellProvider: (UITableView, IndexPath, O) -> UITableViewCell?
}
// MARK: - DefaultTableViewTarget
public struct DefaultTableViewTarget<T: UITableView>: Target {
// MARK: Public
public typealias Base = T
public private(set) weak var base: Base?
public init(_ base: Base) {
self.base = base
}
// MARK: DiffableDataSource.Target
public var shouldSuspendBatchUpdates: Bool {
return self.base?.window == nil
}
public func deleteSections(at indices: IndexSet, animated: Bool) {
self.base?.deleteSections(indices, with: .automatic)
}
public func insertSections(at indices: IndexSet, animated: Bool) {
self.base?.insertSections(indices, with: .automatic)
}
public func reloadSections(at indices: IndexSet, animated: Bool) {
self.base?.reloadSections(indices, with: .automatic)
}
public func moveSection(at index: IndexSet.Element, to newIndex: IndexSet.Element, animated: Bool) {
self.base?.moveSection(index, toSection: newIndex)
}
public func deleteItems(at indexPaths: [IndexPath], animated: Bool) {
self.base?.deleteRows(at: indexPaths, with: .automatic)
}
public func insertItems(at indexPaths: [IndexPath], animated: Bool) {
self.base?.insertRows(at: indexPaths, with: .automatic)
}
public func reloadItems(at indexPaths: [IndexPath], animated: Bool) {
self.base?.reloadRows(at: indexPaths, with: .automatic)
}
public func moveItem(at indexPath: IndexPath, to newIndexPath: IndexPath, animated: Bool) {
self.base?.moveRow(at: indexPath, to: newIndexPath)
}
public func performBatchUpdates(updates: () -> Void, animated: Bool, completion: @escaping () -> Void) {
guard let base = self.base else {
return
}
base.performBatchUpdates(updates, completion: { _ in completion() })
}
public func reloadData() {
self.base?.reloadData()
}
}
}
#endif