fix: table reload in the background cannot keep scroll position issue

This commit is contained in:
CMK 2022-07-15 02:46:48 +08:00
parent 206fe8d3bd
commit 9561b58a70
2 changed files with 15 additions and 157 deletions

View File

@ -155,7 +155,13 @@ extension HomeTimelineViewModel {
) -> Difference<T>? {
guard let sourceIndexPath = (tableView.indexPathsForVisibleRows ?? []).sorted().first else { return nil }
let rectForSourceItemCell = tableView.rectForRow(at: sourceIndexPath)
let sourceDistanceToTableViewTopEdge = tableView.convert(rectForSourceItemCell, to: nil).origin.y - tableView.safeAreaInsets.top
let sourceDistanceToTableViewTopEdge: CGFloat = {
if tableView.window != nil {
return tableView.convert(rectForSourceItemCell, to: nil).origin.y - tableView.safeAreaInsets.top
} else {
return rectForSourceItemCell.origin.y - tableView.contentOffset.y - tableView.safeAreaInsets.top
}
}()
guard sourceIndexPath.section < oldSnapshot.numberOfSections,
sourceIndexPath.row < oldSnapshot.numberOfItems(inSection: oldSnapshot.sectionIdentifiers[sourceIndexPath.section])

View File

@ -139,130 +139,6 @@ extension ThreadViewModel {
} // end Task
}
.store(in: &disposeBag)
// Publishers.CombineLatest3(
// rootItem.removeDuplicates(),
// ancestorItems.removeDuplicates(),
// descendantItems.removeDuplicates()
// )
// .receive(on: RunLoop.main)
// .sink { [weak self] rootItem, ancestorItems, descendantItems in
// guard let self = self else { return }
// var items: [Item] = []
// rootItem.flatMap { items.append($0) }
// items.append(contentsOf: ancestorItems)
// items.append(contentsOf: descendantItems)
// self.updateDeletedStatus(for: items)
// }
// .store(in: &disposeBag)
//
// Publishers.CombineLatest4(
// rootItem,
// ancestorItems,
// descendantItems,
// existStatusFetchedResultsController.objectIDs
// )
// .debounce(for: .milliseconds(100), scheduler: RunLoop.main) // some magic to avoid jitter
// .sink { [weak self] rootItem, ancestorItems, descendantItems, existObjectIDs in
// guard let self = self else { return }
// guard let tableView = self.tableView,
// let navigationBar = self.contentOffsetAdjustableTimelineViewControllerDelegate?.navigationBar()
// else { return }
//
// guard let diffableDataSource = self.diffableDataSource else { return }
// let oldSnapshot = diffableDataSource.snapshot()
//
// var newSnapshot = NSDiffableDataSourceSnapshot<StatusSection, Item>()
// newSnapshot.appendSections([.main])
//
// let currentState = self.loadThreadStateMachine.currentState
//
// // reply to
// if self.rootNode.value?.replyToID != nil, !(currentState is LoadThreadState.NoMore) {
// newSnapshot.appendItems([.topLoader], toSection: .main)
// }
//
// let ancestorItems = ancestorItems.filter { item in
// guard case let .reply(statusObjectID, _) = item else { return false }
// return existObjectIDs.contains(statusObjectID)
// }
// newSnapshot.appendItems(ancestorItems, toSection: .main)
//
// // root
// if let rootItem = rootItem,
// case let .root(objectID, _) = rootItem,
// existObjectIDs.contains(objectID) {
// newSnapshot.appendItems([rootItem], toSection: .main)
// }
//
// // leaf
// if !(currentState is LoadThreadState.NoMore) {
// newSnapshot.appendItems([.bottomLoader], toSection: .main)
// }
//
// let descendantItems = descendantItems.filter { item in
// switch item {
// case .leaf(let statusObjectID, _):
// return existObjectIDs.contains(statusObjectID)
// default:
// return true
// }
// }
// newSnapshot.appendItems(descendantItems, toSection: .main)
//
// // difference for first visible item exclude .topLoader
// guard let difference = self.calculateReloadSnapshotDifference(navigationBar: navigationBar, tableView: tableView, oldSnapshot: oldSnapshot, newSnapshot: newSnapshot) else {
// diffableDataSource.apply(newSnapshot)
// return
// }
//
// // additional margin for .topLoader
// let oldTopMargin: CGFloat = {
// let marginHeight = TimelineTopLoaderTableViewCell.cellHeight
// if oldSnapshot.itemIdentifiers.contains(.topLoader) {
// return marginHeight
// }
// if !ancestorItems.isEmpty {
// return marginHeight
// }
//
// return .zero
// }()
//
// let oldRootCell: UITableViewCell? = {
// guard let rootItem = rootItem else { return nil }
// guard let index = oldSnapshot.indexOfItem(rootItem) else { return nil }
// guard let cell = tableView.cellForRow(at: IndexPath(row: index, section: 0)) else { return nil }
// return cell
// }()
// // save height before cell reuse
// let oldRootCellHeight = oldRootCell?.frame.height
//
// diffableDataSource.reloadData(snapshot: newSnapshot) {
// guard let _ = rootItem else {
// return
// }
// if let oldRootCellHeight = oldRootCellHeight {
// // set bottom inset. Make root item pin to top (with margin).
// let bottomSpacing = tableView.safeAreaLayoutGuide.layoutFrame.height - oldRootCellHeight - oldTopMargin
// tableView.contentInset.bottom = max(0, bottomSpacing)
// }
//
// // set scroll position
// tableView.scrollToRow(at: difference.targetIndexPath, at: .top, animated: false)
// let contentOffsetY: CGFloat = {
// var offset: CGFloat = tableView.contentOffset.y - difference.offset
// if tableView.contentInset.bottom != 0.0 && descendantItems.isEmpty {
// // needs restore top margin if bottom inset adjusted AND no descendantItems
// offset += oldTopMargin
// }
// return offset
// }()
// tableView.setContentOffset(CGPoint(x: 0, y: contentOffsetY), animated: false)
// }
// }
// .store(in: &disposeBag)
}
}
@ -379,7 +255,13 @@ extension ThreadViewModel {
let sourceIndexPath = IndexPath(row: index, section: 0)
let rectForSourceItemCell = tableView.rectForRow(at: sourceIndexPath)
let sourceDistanceToTableViewTopEdge = tableView.convert(rectForSourceItemCell, to: nil).origin.y - tableView.safeAreaInsets.top
let sourceDistanceToTableViewTopEdge: CGFloat = {
if tableView.window != nil {
return tableView.convert(rectForSourceItemCell, to: nil).origin.y - tableView.safeAreaInsets.top
} else {
return rectForSourceItemCell.origin.y - tableView.contentOffset.y - tableView.safeAreaInsets.top
}
}()
guard sourceIndexPath.section < oldSnapshot.numberOfSections,
sourceIndexPath.row < oldSnapshot.numberOfItems(inSection: oldSnapshot.sectionIdentifiers[sourceIndexPath.section])
@ -403,33 +285,3 @@ extension ThreadViewModel {
)
}
}
//extension ThreadViewModel {
// private func updateDeletedStatus(for items: [Item]) {
// let parentManagedObjectContext = context.managedObjectContext
// let managedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
// managedObjectContext.parent = parentManagedObjectContext
// managedObjectContext.perform {
// var statusIDs: [Status.ID] = []
// for item in items {
// switch item {
// case .root(let objectID, _):
// guard let status = managedObjectContext.object(with: objectID) as? Status else { continue }
// statusIDs.append(status.id)
// case .reply(let objectID, _):
// guard let status = managedObjectContext.object(with: objectID) as? Status else { continue }
// statusIDs.append(status.id)
// case .leaf(let objectID, _):
// guard let status = managedObjectContext.object(with: objectID) as? Status else { continue }
// statusIDs.append(status.id)
// default:
// continue
// }
// }
// DispatchQueue.main.async { [weak self] in
// guard let self = self else { return }
// self.existStatusFetchedResultsController.statusIDs.value = statusIDs
// }
// }
// }
//}