Dear Experts, NSLocale has a notification NSCurrentLocaleDidChangeNotification and a property autoupdatingCurrentLocale ("A locale which tracks the user’s current preferences"). These suggest that an app should be able to detect when the user changes their language preference while running, or when it is resumed from the background. In practice, when I change language in the Settings app (either globally or just for my app), the app is terminated by iOS and restarts with new locale. Is this the expected behaviour? I am wondering if there is something I need to do to advertise that the app can adopt language changes without restarting, or something. Maybe only date-time formats, etc., trigger the notification but language changes don't?

I've just downloaded Xcode 15 (3.18 GB), and when I start it it downloads "additional components". It's currently downloading "iOS 17.0 Simulator" (7.56 GB). I don't need the simulator, but I do need to compile for iOS and run on devices. Do I need this "simulator" download? I note that while the small download progress window says "iOS 17.0 Simulator (21A328)", the main Xcode window won't let me compile/run the project because it is "Downloading iOS 17.0..." - though I'm not sure if the "..." at the end of that is a truncation eliding the word "Simulator".

I'm referring to the use of a "settings bundle" plist to cause the main Settings app to display your app's preferences which the app can then read via NSUserDefaults, as described here: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/UserDefaults/Preferences/Preferences.html#//apple_ref/doc/uid/10000059i-CH6 I am wondering if this is actually deprecated, or something. I ask because, (1), it still has the high-quality old-style documentation, and (2) there doesn't seem to be a "required reason API" code for using it. Specifically, the NSUserDefaults required reason API codes are CA92.1 : "This reason does not permit reading information that was written by other apps or the system" 1C8F.1 : "This reason does not permit reading information that was written by apps, app extensions, or App Clips outside the same App Group or by the system." C56D.1: "...third-party SDK..." - nope. AC6B.1: "... com.apple.configuration.managed ..." - nope. None of the codes permit reading preferences that have been set by the Settings app using this method.

Dear Experts, In "limited access" photos mode, I present a PHPickerViewController. It shows the entire photo library, with a note at the top saying that the app can only access the items that I select. I select a photo. In the delegate method, I get a PHPickerResult containing a plausible-looking string for the assetIdentifier. It's the same string that I get for that photo in "full access" mode. Should this photo now be accessible, or do I need to do something else at this point? When I call fetchAssetsWithLocalIdentifiers using this assetIdentifier, I get no results. When I call cloudIdentifierMappingsForLocalIdentifiers, I get error PHPhotosErrorIdentifierNotFound. In "full access" mode, both work OK. What am I missing? Thanks.

I'm using CMMotionManager startDeviceMotionUpdatesUsingReferenceFrame: CMAttitudeReferenceFrameXTrueNorthZVertical and have set the NSMotionUsageDescription ("Privacy - Motion Usage Description") property in the info.plist. But I don't see a permissions popup. I also don't see any mention of this in the app's section of the Settings app. When is this usage description string used? I wonder if there is some connection between the motion permission and the location permission, which I also use?

Does anyone know how battery state notification (UIDevice.batteryStateDidChangeNotification) is supposed to work regarding app foreground/background state? Assume there is no other reason why the app is running in the background. I have enabled UIDevice.current.isBatteryMonitoringEnabled when the app was in the foreground. What should happen if the external power is later connected or removed when the app is in the background? The docs don't mention this. Possibilities include I don't get a notification, so I should check the state myself when the app next comes to the foreground. I'll get a notification when the app next comes to the foreground, if the state changed while it was in the background. The app will be woken up in the background to receive the notification. The app will be kept running in the background while isBatteryMonitoringEnabled is true. It looks as if it's doing either 3 or 4, which I find a bit surprising. But is this influenced by the fact that it's connected (wirelessly) to the debugger?

Dear Experts, I have been looking at thr SimpleWatchConnectivity sample code: https://developer.apple.com/documentation/watchconnectivity/transferring-data-with-watch-connectivity There are a couple of things in there that look out of date. Firstly, it uses a WKApplicationDelegate to receive the background tasks. I believe this can probably be entirely removed, and replaced with .backgroundTask(.watchConnectivity) { ... } on the App. Is that true? What do I need something inside the { ... } there? Secondly, it is using NSNotificationCenter to send received data from the WCSessionDelegate to the SwiftUI view hierarchy. Is there a better way to do that? I have spent a while trying to work out how a WCSessionDelegate class can connect to a binding to a SwiftUI @State property, and cause the UI to update in response to received data, but I haven't made it work. Are there any newer examples of how to do this? I'm currently only trying to send some simple applicationContext state from the phone to the watch and have some views update to show the latest values. Thanks, Phil.

Consider this Swift struct: public struct Example { public func foo(callback: ()->Void) { .... } public func blah(i: Int) { .... } .... } Using Swift/C++ interop, I can create Example objects and call methods like blah. But I can't call foo because Swift/C++ interop doesn't currently support passing closures (right?). On the other hand, Swift/objC does support passing objC blocks to Swift functions. But I can't use that here because Example is a Swift struct, not a class. So I could change it to a class, and update everything to work with reference rather than value semantics; but then I also have to change the objC++ code to create the object and call its methods using objC syntax. I'd like to avoid that. Is there some hack that I can use to make this possible? I'm hoping that I can wrap a C++ std::function in some sort of opaque wrapper and pass that to swift, or something. Thanks for any suggestions!

I would like to be able to write something like: struct FooView: View { let foo: Foo; var body: some View { assert(foo.valid); ...... } }; but of course I can't, because "Type () cannot conform to View". What's the best way to achieve this?

I'm fed up with this. I write a detailed message and press Submit, and I get that. I press back, and my composition is gone. I think it happens most often when I've logged in only recently, i.e. I've read a few posts, decide to reply to one and log in. At that point, if I close everything and start again and find the thread I want to reply to then it works. But if I don't do that then I run the risk of being told I'm "unauthorized" and losing whatever I've written. This isn't rocket science! Why do we put up with it?

I have a simple Safari extension which contains only Javascript and no native code. Currently I have the placeholder SafariWebExtensionHandler.swift that Xcode created when I added the extension. It's not doing anything useful, but simply deleting it doesn't seem to work. Can I have an extension that includes no native code?

I have a file on my Mac of a slightly unusual type. Let's say it's an "XYZ" file. Maybe I downloaded it from somewhere. I don't have any programs on my Mac that know about XYZ files, so if I view it in Finder is is shown with a plain icon and a generic description e.g. "Document". If I check its type, it seems that macOS has allocated it a "dyn.*" UTI: % mdls -name kMDItemContentType ~/foo.xyz kMDItemContentType = "dyn.ah62d4rv4ge81u8p4" I do have an app on my iPad that knows about XYZ files. The app has a UTImportedTypeDeclarations entry for .xyz in its Info.plist. I transfer the file to my iPad using AirDrop. Annoyingly, the iPad does not offer to open the file with the appropriate app. It seems to me that the iPad has blindly trusted the dyn.* UTI that macOS allocated for the file, and which presumably has been sent by AirDrop. It has not used the filename extension mapping from its app's Info.plist to determine that the file is an XYZ file. That may be considered a bug in iOS but that's not my question... My question is: is there anything that I can do on my Mac to tell it that this file foo.xyz is of type UTI com.example.xyz ? I was expecting to find either an md... command to modify the metadata, including the UTI, for a file, or some way to do this by setting an extended attribute. I have not yet found either. Any ideas anyone?

Dear Experts, We are required to remove our NSFilePresenters from the NSFileCoordinator when the app goes to the background and re-add them when it returns to the foreground. Does this mean that when we foreground, we need to manually check if our files have been modified, deleted, or moved in the meantime? Or is there some mechanism in NSFilePresenter/NSFileCoordinator that will report any such changes to us? Detecting that a file has been modified or deleted is not difficult, but I don't think it's possible to detect that it has moved. Changes to directories are also difficult. Any advice? What does UIDocument do in this case?

Dear All, Does anyone have any suggestions for an iPad text editor app that is well-behaved with respect to NSFileCoordinator / NSFilePresenter / UIDocument etc.? Specifically, I'd like something that I can run in iPad split screen mode alongside my test app. I'd like to be able to make changes to files using the text editor and see my test app pick them up, and vice-versa. I am currently trying an app called "Quick Text" which mostly works but it doesn't seem to pick up changes that I make in my test app unless I close and re-open the file at its end. I'm also soon going to reach its limit of "10 edits per week"! I have a couple of others to try, but maybe someone here has a suggestion?

I believe that if I rename a file, I'm supposed to do that inside a coordinated write on the parent directory - right? So say I have a file /path/to/folder/f1 and I want to rename it (in the same directory) as /path/to/folder/f2. I do a coordinated write (with the forMoving option) on the directory /path/to/folder. That passes me a possibly different path to the directory, right? Say I get /path/to/different. Question: what rename should I actually do? Do I need to construct from and to paths based on the different path that is passed to the accessor? I.e. do I rename from /path/to/folder/f1 to /path/to/folder/f2 or rename from /path/to/different/f1 to /path/to/different/f2 or some other combination? Do NSFileManager's renaming methods do anything special in this regard? Can I use e.g. std::filesystem::rename()? I am interested in both local documents that are visible e.g. in the Files app, and iCloud Drive documents, if that makes any difference. Thanks!