User Profile

I am having a problem trying to resolve a problem with an associated type in a protocol. Here is the code stripped down to minimum for demonstration protocol Protocol1 { associatedtype DataItem func protocolMethod(item : DataItem) } protocol Protocol2 { associatedtype AType1: Hashable //... } class Class1<Type1: Protocol2>: NSObject { typealias Item = Type1.AType1 var delegate : (any Protocol1)? private func method1(item: Item) { delegate?.protocolMethod(item : item) //ERROR HERE } } The error occurring at "ERROR HERE" is: Member 'protocolMethod' cannot be used on value of type 'any Protocol1'; consider using a generic constraint instead This all works if the item parameter is not defined on protocolMethod (and its invocation where the error occurs). And I think I get why it's happening, that it can't determine the type of item in the invocation. Is there a way to accomplish this? I have played with it quite a bit with generic params, etc. but still can't find the right formula to make it work. Am I just asking too much from Swift in this case?

Currently pretty confused about a DiffableDatasource, FetchedResultsController, &amp; CollectionView behavior. As a result of calling the method below, the NSFetchedResultsController delegate didChangeContentWith method is called with a snapshot that contains temporary NSManagedObjectIds. As a result, when cell registration vend block is called, it is given the temporary id as the item id which no longer is valid as the object has been saved. So trying to retrieve the object to create the configuration for the cell fails. Here is snippet of the log produced by the code below (adding 2 new items): pre-save didChangeContentWith Printing description of snapshot: NSDiffableDataSourceSnapshot 0x2838cb660: numberOfSections:1 numberOfItems:5; generation=4EAC45D6-A145-4F4C-8220-F6EE212C3F88; sectionCounts=[_UIDataSourceSnapshotter - 0x283ab3fe0:(0:5)] [d69e6c783a242772974cfc99189691b88e9d37c3: {0x94cd5e7b72fa7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p2 0x94cd5e7b729a7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p1 0x94cd5e7b72da7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p3 0x283a5a8e0 x-coredata:///PlaylistItem/t710323F2-7D5C-40C4-A055-F75F8E0D0C852 0x283aaf8a0 x-coredata:///PlaylistItem/t710323F2-7D5C-40C4-A055-F75F8E0D0C853}] post save getting cell for [0, 0] with objid: 0x94cd5e7b72fa7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p2 getting cell for [0, 1] with objid: 0x94cd5e7b729a7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p1 getting cell for [0, 2] with objid: 0x94cd5e7b72da7e83 x-coredata://988F6C04-1529-454C-BBCB-2DE610F7AFC0/PlaylistItem/p3 getting cell for [0, 3] with objid: 0x283a5a8e0 x-coredata:///PlaylistItem/t710323F2-7D5C-40C4-A055-F75F8E0D0C852 Fatal error: Managed object should be available: file Stoppage/PlaylistDetail2FRCViewModel.swift, line 118 2021-05-05 11:43:10.611464-0500 Stoppage[5055:2243531] Fatal error: Managed object should be available: file Stoppage/PlaylistDetail2FRCViewModel.swift, line 118 The datasource is passing the temporary id (which is no longer available post save) to the cell creation. I can fully accept that I might be being dim and not seeing my mistake, but I just can't see it. It seems to me that the snapshot generated from the save should have the real objectIds rather than the temps. The end result is that the fatalError() in the cell registration is called as it can't find the object with the temp id. Insert items method     func addItemsToPlaylist(_ newItemCollection:MPMediaItemCollection)     {         guard let playlist = self.playlist else {fatalError()}       AppDelegate.appDelegate().persistentContainer.viewContext.performAndWait {             let pl = AppDelegate.appDelegate().persistentContainer.viewContext.object(with: playlist.objectID) as! Playlist             pl.addMediaItems(newItemCollection)             if AppDelegate.appDelegate().persistentContainer.viewContext.hasChanges {                 do {                     print("pre-save")                     try AppDelegate.appDelegate().persistentContainer.viewContext.save()                     print("post save")                 } catch {                     let nserror = error as NSError                     fatalError("Unresolved error \(nserror), \(nserror.userInfo)")                 }             }         }     } didChangeContent method     func controller(_ controller: NSFetchedResultsControllerNSFetchRequestResult, didChangeContentWith snapshot: NSDiffableDataSourceSnapshotReference) {          print("didChangeContentWith")          guard let datasource = diffableDataSource else {             assertionFailure("The data source has not implemented snapshot support while it should")             return         }             datasource.apply(snapshot as NSDiffableDataSourceSnapshotInt, NSManagedObjectID, animatingDifferences: false)     } Cell Registration         let itemCellRegistration = UICollectionView.CellRegistrationPlaylistDetail2Cell, NSManagedObjectID { (cell, indexPath, itemId) in             guard let object = try? AppDelegate.appDelegate().persistentContainer.viewContext.existingObject(with: itemId) else {                 fatalError("Managed object should be available")             }             cell.playlistItem = object as! PlaylistItem             cell.playlistItemId = object.objectID         }

Trying to figure out the best way to update an CoreData app to use Cloud Kit.Right now I have a ObjectA entity defined as the top level object. There is a Photo entity that contains a Binary Data attribute for the thumbnail and a URI for the location of the full image. So bascially that setup is a lot like a CKAsset in CloudKit and CKAsset would seem to be the logical way to get the images to sync between devices.I can't find anything along those lines relating to NSPersistentCloudKitContainer though. As the model is taken from Core Data model you can't really predefine an asset attribute. So would the approach be to get the CKRecord and directly add the CKAsset that way? Would there be repercussions related to the Container if you did that?And if there is some simpler way I am missing please let me know. I am aware I can do a Binary Data attribute, I had done that earlier in the app's life and it didn't work as well as just providing the URI for the image and managing the data myself. Or would that be the right thing to do and go back to a Binary Data attribute to save the image data?

Trying to set up a test app using NSPersistentCloudKitContainer. Once I got the container set up, got error that attributes must be Optional or provide a default value, which makes sense. Problem is I have one Entity that has a Binary Data field. The field has been marked as Optional.However, the DataModelCompile build step complains that "Photo.image must have a default value" Also get a "CloudKit Integration" error along the same lines: "Photo.image must have a default value".But there is no way to define a default value for a Binary Data attribute, so don't see a way to fulfill this.Anybody got a clue or do you think its just something I should Radar?

Having a problem with NavigationButton specified in .navigationBarItems(trailing:). The following code renders as expected with "Froom" on the right side of nav bar, and it is a button. But if tapped, nothing happens.struct NavButton : View { var body: some View { Text("Froom") } } struct ContentView : View { var body: some View { NavigationView { List(0 ..&lt; 5) { item in ProjectCell() }.navigationBarTitle(Text("Project")) .navigationBarItems(trailing: NavigationButton(destination: ProjectDetail()){ NavButton()}) } } }However, if I do the followingstruct ContentView : View { var body: some View { //!!!adding this NavigationView { NavigationButton(destination: ProjectDetail()) { NavButton() } //!!! List(0 ..&lt; 5) {item in ProjectCell() }.navigationBarTitle(Text("Project")) .navigationBarItems(trailing: NavigationButton(destination: ProjectDetail()){ NavButton()}) } } }Placing the same thing in the main view, the button navigates as expected when tapped. So my question is this: Is .navigationBarItems(trailing:) not working properly? Or am I misusing it?