I have a UITableVIew with a UITableViewDiffableDataSource. The tableView also uses and custom Cell Class.
Adding Items essentially works. By tapping and holding a cell I go to a viewController where I can update/change several fields of my item. Here's the method used :
Two options:
1) With all of the above code in place, the changes are reflected in the tableView, but ONLY when the
2) if I omit the if
the changes are also reflected immediately, but the console throws a warning:
[UIDiffableDataSource] Warning: 1 inserted identifier(s) already present; existing items will be moved into place for this current insertion. Please note this will impact performance if items are not unique when inserted.
TL;DR What's the correct way of updating an existing item when using a UITableViewDiffableDataSource?
ALSO, on a side note: when I insert the very first item into the DataSource/Snapshot I get a warning also
I thought that forcing the .apply() on the main thread should prevent that? Programmatic UI, no storyboards, I do add tableView as subview to the view!
Adding Items essentially works. By tapping and holding a cell I go to a viewController where I can update/change several fields of my item. Here's the method used :
Code Block func save(_ annotation: Annotation, withMapImage mapImage: AnnotationsController.MapImage?) { //Save the project to update Last Edited projectsController.save(annotationsController.project, withImage: nil) //Get current snapshot var snapshot = dataSource.snapshot() //Replace updated annotation by deleting old version from snapshot first if snapshot.itemIdentifiers.contains(annotation) { snapshot.deleteItems([annotation]) } snapshot.appendItems([annotation], toSection: annotation.type) //Apply the snapshot on the main thread DispatchQueue.main.async { self.dataSource.apply(snapshot, animatingDifferences: true) self.tableView.reloadData() } //Save to storage annotationsController.save(annotation, withMapImage: nil) }
Two options:
1) With all of the above code in place, the changes are reflected in the tableView, but ONLY when the
Code Block self.tableView.reloadData()
2) if I omit the if
Code Block snapshot.itemIdentifiers.contains(annotation) { ...
the changes are also reflected immediately, but the console throws a warning:
[UIDiffableDataSource] Warning: 1 inserted identifier(s) already present; existing items will be moved into place for this current insertion. Please note this will impact performance if items are not unique when inserted.
TL;DR What's the correct way of updating an existing item when using a UITableViewDiffableDataSource?
ALSO, on a side note: when I insert the very first item into the DataSource/Snapshot I get a warning also
Code Block TableView] Warning once only: UITableView was told to layout its visible cells and other contents without being in the view hierarchy (the table view or one of its superviews has not been added to a window). This may cause bugs by forcing views inside the table view to load and perform layout without accurate information (e.g. table view bounds, trait collection, layout margins, safe area insets, etc), and will also cause unnecessary performance overhead due to extra layout passes. Make a symbolic breakpoint at UITableViewAlertForLayoutOutsideViewHierarchy to catch this in the debugger and see what caused this to occur, so you can avoid this action altogether if possible, or defer it until the table view has been added to a window. Table view: <UITableView: 0x7f9213826200; frame = (0 0; 414 896); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x6000035ff780>;
I thought that forcing the .apply() on the main thread should prevent that? Programmatic UI, no storyboards, I do add tableView as subview to the view!
