Add DiffableTimelineLikeTableViewController

This commit is contained in:
Shadowfacts 2021-06-20 22:27:29 -04:00
parent ebb0770198
commit 49572c1fec
3 changed files with 274 additions and 2 deletions

View File

@ -155,6 +155,7 @@
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D6531DF0246B867E000F9538 /* GifvAttachmentViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */; }; D6531DF0246B867E000F9538 /* GifvAttachmentViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */; };
D6538945214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */; }; D6538945214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */; };
D653F411267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */; };
D65C6BF525478A9C00A6E89C /* BackgroundableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */; }; D65C6BF525478A9C00A6E89C /* BackgroundableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */; };
D65F613423AEAB6600F3CFD3 /* OnboardingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65F613323AEAB6600F3CFD3 /* OnboardingTests.swift */; }; D65F613423AEAB6600F3CFD3 /* OnboardingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65F613323AEAB6600F3CFD3 /* OnboardingTests.swift */; };
D6620ACE2511A0ED00312CA0 /* StatusStateResolver.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6620ACD2511A0ED00312CA0 /* StatusStateResolver.swift */; }; D6620ACE2511A0ED00312CA0 /* StatusStateResolver.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6620ACD2511A0ED00312CA0 /* StatusStateResolver.swift */; };
@ -553,6 +554,7 @@
D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentView.swift; sourceTree = "<group>"; }; D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentView.swift; sourceTree = "<group>"; };
D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentViewController.swift; sourceTree = "<group>"; }; D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentViewController.swift; sourceTree = "<group>"; };
D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewSwipeActionProvider.swift; sourceTree = "<group>"; }; D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewSwipeActionProvider.swift; sourceTree = "<group>"; };
D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DiffableTimelineLikeTableViewController.swift; sourceTree = "<group>"; };
D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackgroundableViewController.swift; sourceTree = "<group>"; }; D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackgroundableViewController.swift; sourceTree = "<group>"; };
D65F612D23AE990C00F3CFD3 /* Embassy.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Embassy.framework; sourceTree = BUILT_PRODUCTS_DIR; }; D65F612D23AE990C00F3CFD3 /* Embassy.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Embassy.framework; sourceTree = BUILT_PRODUCTS_DIR; };
D65F613023AE99E000F3CFD3 /* Ambassador.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Ambassador.framework; sourceTree = BUILT_PRODUCTS_DIR; }; D65F613023AE99E000F3CFD3 /* Ambassador.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Ambassador.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@ -1485,6 +1487,7 @@
D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */, D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */,
D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */, D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */,
D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */, D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */,
D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */,
D625E4812588262A0074BB2B /* DraggableTableViewCell.swift */, D625E4812588262A0074BB2B /* DraggableTableViewCell.swift */,
D6A6C10425B6138A00298D0F /* StatusTablePrefetching.swift */, D6A6C10425B6138A00298D0F /* StatusTablePrefetching.swift */,
); );
@ -2151,6 +2154,7 @@
D626493823C0FD0000612E6E /* AllPhotosTableViewCell.swift in Sources */, D626493823C0FD0000612E6E /* AllPhotosTableViewCell.swift in Sources */,
D627943B23A55BA600D38C68 /* NavigableTableViewCell.swift in Sources */, D627943B23A55BA600D38C68 /* NavigableTableViewCell.swift in Sources */,
D6333B792139AEFD00CE884A /* Date+TimeAgo.swift in Sources */, D6333B792139AEFD00CE884A /* Date+TimeAgo.swift in Sources */,
D653F411267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift in Sources */,
D6C82B5625C5F3F20017F1E6 /* ExpandThreadTableViewCell.swift in Sources */, D6C82B5625C5F3F20017F1E6 /* ExpandThreadTableViewCell.swift in Sources */,
D686BBE324FBF8110068E6AA /* WrappedProgressView.swift in Sources */, D686BBE324FBF8110068E6AA /* WrappedProgressView.swift in Sources */,
D620483423D3801D008A63EF /* LinkTextView.swift in Sources */, D620483423D3801D008A63EF /* LinkTextView.swift in Sources */,

View File

@ -0,0 +1,268 @@
//
// DiffableTimelineLikeTableViewController.swift
// Tusker
//
// Created by Shadowfacts on 6/18/21.
// Copyright © 2021 Shadowfacts. All rights reserved.
//
import UIKit
import Pachyderm
class DiffableTimelineLikeTableViewController<Section: Hashable & CaseIterable, Item: Hashable>: EnhancedTableViewController, RefreshableViewController {
typealias Snapshot = NSDiffableDataSourceSnapshot<Section, Item>
typealias LoadResult = Result<Snapshot, LoadError>
private let pageSize = 20
private(set) var state = State.unloaded
private var lastLastVisibleRow: IndexPath?
private(set) var dataSource: UITableViewDiffableDataSource<Section, Item>!
init() {
super.init(style: .plain)
addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: Self.refreshCommandTitle()))
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
dataSource = UITableViewDiffableDataSource(tableView: tableView, cellProvider: self.cellProvider)
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 140
#if !targetEnvironment(macCatalyst)
self.refreshControl = UIRefreshControl()
self.refreshControl!.addTarget(self, action: #selector(refresh), for: .valueChanged)
#endif
if let prefetchSource = self as? UITableViewDataSourcePrefetching {
tableView.prefetchDataSource = prefetchSource
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
loadInitial()
}
override func viewDidDisappear(_ animated: Bool) {
super.viewDidDisappear(animated)
pruneOffscreenRows()
}
class func refreshCommandTitle() -> String {
return "Refresh"
}
private func pruneOffscreenRows() {
guard let lastVisibleRow = lastLastVisibleRow else {
return
}
var snapshot = dataSource.snapshot()
let lastVisibleRowSection = snapshot.sectionIdentifiers[lastVisibleRow.section]
let contentSections = snapshot.sectionIdentifiers.filter { timelineContentSections().contains($0) }
guard let lastVisibleContentSectionIndex = contentSections.lastIndex(of: lastVisibleRowSection) else {
return
}
if lastVisibleContentSectionIndex < contentSections.count - 1 {
// there are more content sections below the current last visible one
let sectionsToRemove = contentSections[lastVisibleContentSectionIndex...]
snapshot.deleteSections(Array(sectionsToRemove))
willRemoveItems(sectionsToRemove.flatMap(snapshot.itemIdentifiers(inSection:)))
} else if lastVisibleContentSectionIndex == contentSections.count - 1 {
let items = snapshot.itemIdentifiers(inSection: lastVisibleRowSection)
if lastVisibleRow.row < items.count - pageSize {
let itemsToRemove = Array(items.suffix(pageSize))
snapshot.deleteItems(itemsToRemove)
willRemoveItems(itemsToRemove)
} else {
return
}
} else {
return
}
dataSource.apply(snapshot, animatingDifferences: false)
}
private func loadInitial() {
guard state == .unloaded else { return }
// set loaded immediately so we don't trigger another request while the current one is running
state = .loadingInitial
loadInitialItems() { result in
guard case let .success(snapshot) = result else {
self.state = .unloaded
return
}
DispatchQueue.main.async {
self.dataSource.apply(snapshot, animatingDifferences: false)
self.state = .loaded
}
}
}
func reloadInitial() {
state = .unloaded
loadInitial()
}
func loadOlder() {
guard state != .loadingOlder else { return }
state = .loadingOlder
loadOlderItems(currentSnapshot: dataSource.snapshot()) { result in
guard case let .success(snapshot) = result else {
self.state = .loaded
return
}
DispatchQueue.main.async {
self.dataSource.apply(snapshot, animatingDifferences: false)
self.state = .loaded
}
}
}
func cellHeightChanged() {
// causes the table view to recalculate the cell heights
tableView.beginUpdates()
tableView.endUpdates()
}
// MARK: - UITableViewDelegate
override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
// this assumes that indexPathsForVisibleRows is always in order
lastLastVisibleRow = tableView.indexPathsForVisibleRows?.last
if indexPath.section == tableView.numberOfSections - 1,
indexPath.row == tableView.numberOfRows(inSection: indexPath.section) - 1 {
loadOlder()
}
}
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
}
override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
}
// MARK: - RefreshableViewController
func refresh() {
guard state != .loadingNewer else { return }
state = .loadingNewer
let snapshot = dataSource.snapshot()
var item: Item? = nil
for section in timelineContentSections() {
if let first = snapshot.itemIdentifiers(inSection: section).first {
item = first
break
}
}
loadNewerItems(currentSnapshot: snapshot) { result in
guard case let .success(snapshot) = result else {
DispatchQueue.main.async {
self.refreshControl?.endRefreshing()
self.state = .loaded
}
return
}
DispatchQueue.main.async {
self.refreshControl?.endRefreshing()
self.dataSource.apply(snapshot, animatingDifferences: false)
self.state = .loaded
if let item = item,
let indexPath = self.dataSource.indexPath(for: item) {
// maintain the current position in the list (don't scroll to top)
self.tableView.scrollToRow(at: indexPath, at: .top, animated: false)
}
}
}
}
// MARK: - Subclass Methods
func cellProvider(_ tableView: UITableView, _ indexPath: IndexPath, _ item: Item) -> UITableViewCell? {
fatalError("cellProvider(_:_:_:) must be implemented by subclasses")
}
func loadInitialItems(completion: @escaping (LoadResult) -> Void) {
fatalError("loadInitialItems(completion:) must be implemented by subclasses")
}
func loadOlderItems(currentSnapshot: Snapshot, completion: @escaping (LoadResult) -> Void) {
fatalError("loadOlderItesm(completion:) must be implemented by subclasses")
}
func loadNewerItems(currentSnapshot: Snapshot, completion: @escaping (LoadResult) -> Void) {
fatalError("loadNewerItems(completion:) must be implemented by subclasses")
}
func timelineContentSections() -> Section.AllCases {
return Section.allCases
}
func willRemoveItems(_ items: [Item]) {
}
}
extension DiffableTimelineLikeTableViewController {
enum State: Equatable {
case unloaded
case loadingInitial
case loaded
case loadingNewer
case loadingOlder
}
}
extension DiffableTimelineLikeTableViewController {
enum LoadError: LocalizedError {
case noClient
case noOlder
case noNewer
case client(Client.Error)
}
}
extension DiffableTimelineLikeTableViewController: BackgroundableViewController {
func sceneDidEnterBackground() {
pruneOffscreenRows()
}
}

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@ -9,8 +9,8 @@
import UIKit import UIKit
/// A table view controller that manages common functionality between timeline-like UIs. /// A table view controller that manages common functionality between timeline-like UIs.
// For example, this class handles loading new items when the user scrolls to the end, /// For example, this class handles loading new items when the user scrolls to the end,
// refreshing, and pruning offscreen rows automatically. /// refreshing, and pruning offscreen rows automatically.
class TimelineLikeTableViewController<Item>: EnhancedTableViewController, RefreshableViewController { class TimelineLikeTableViewController<Item>: EnhancedTableViewController, RefreshableViewController {
private(set) var loaded = false private(set) var loaded = false