I have an iOS app that can play audio books as FairPlay DRM'd audio streams. I'm using AVContentKeySession to fetch keys and AVQueuePlayer to play. It works great on iOS, but on Catalyst (Monterey 12.3.1, M1 Max MacBook Pro) it crashes. When it happens in debug, I get a message "Too few bits left in input buffer" printed to the console, and an exception is thrown in the guts of what appears to be core media. Here's the output from [NSThread callStackSymbols] when paused on an exception breakpoint at that point: 0   ???                       0x0000000156b8cc9c 0x0 + 5749918876, 1   BRFree                    0x000000010445cf08 main + 0, 2   AudioCodecs               0x0000000157918c24 _ZL11GetPropertyPvjPjS_ + 52, 3   AudioToolboxCore          0x00000001862536a4 _ZN15ADTSAudioStream11ParseHeaderER27AudioFileStreamContinuation + 1060, 4   AudioToolboxCore          0x000000018624259c AudioFileStreamParseBytes + 412, 5   MediaToolbox              0x00000001915f7d98 FigManifoldCreateForICY + 2176, 6   MediaToolbox              0x00000001915f7718 FigManifoldCreateForICY + 512, 7   MediaToolbox              0x00000001916bbd78 FigPlayerStreamCreate + 315920, 8   MediaToolbox              0x0000000191a269a0 FigMetadataConverterCreateForQuickTimeToFromiTunes + 45888, 9   MediaToolbox              0x0000000191a4a290 FigMetadataConverterCreateForQuickTimeToFromiTunes + 191536, 10  MediaToolbox              0x0000000191a2a470 FigMetadataConverterCreateForQuickTimeToFromiTunes + 60944, 11  MediaToolbox              0x0000000191a28c34 FigMetadataConverterCreateForQuickTimeToFromiTunes + 54740, 12  MediaToolbox              0x0000000191a413b4 FigMetadataConverterCreateForQuickTimeToFromiTunes + 154964, 13  MediaToolbox              0x0000000191a2f144 FigMetadataConverterCreateForQuickTimeToFromiTunes + 80612, 14  MediaToolbox              0x00000001917cae64 FigAlternateFilterMonitorCreateForThermalNotification + 30428, 15  MediaToolbox              0x00000001917ccb44 FigAlternateFilterMonitorCreateForThermalNotification + 37820, 16  MediaToolbox              0x00000001917cb134 FigAlternateFilterMonitorCreateForThermalNotification + 31148, 17  CFNetwork                 0x0000000189937cd4 _CFHostIsDomainTopLevelForCertificatePolicy + 27728, 18  Foundation                0x0000000185ba980c __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 24, 19  Foundation                0x0000000185ba96b4 -[NSBlockOperation main] + 104, 20  Foundation                0x0000000185ba9644 __NSOPERATION_IS_INVOKING_MAIN__ + 24, 21  Foundation                0x0000000185ba88dc -[NSOperation start] + 788, 22  Foundation                0x0000000185ba85c0 __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 24, 23  Foundation                0x0000000185ba8478 __NSOQSchedule_f + 184, 24  libdispatch.dylib         0x00000001099f60f4 _dispatch_block_async_invoke2 + 148, 25  libdispatch.dylib         0x00000001099e2394 _dispatch_client_callout + 20, 26  libdispatch.dylib         0x00000001099eb778 _dispatch_lane_serial_drain + 980, 27  libdispatch.dylib         0x00000001099ec814 _dispatch_lane_invoke + 492, 28  libdispatch.dylib         0x00000001099f9fc8 _dispatch_root_queue_drain + 408, 29  libdispatch.dylib         0x00000001099f9d3c _dispatch_worker_thread + 264, 30  libsystem_pthread.dylib   0x00000001094e1890 _pthread_start + 148, 31  libsystem_pthread.dylib   0x00000001094ebaa8 thread_start + 8 In the Debug Navigator, the top of the stack looks a little different: #0 0x0000000184bdeb3c in __cxa_throw () #1 0x000000015791941c in ACMP4AACLowComplexityDecoder::GetProperty(unsigned int, unsigned int&, void*) () #2 0x0000000157918c24 in GetProperty(void*, unsigned int, unsigned int*, void*) () #3 0x00000001862536a4 in ADTSAudioStream::ParseHeader(AudioFileStreamContinuation&) () #4 0x000000018624259c in AudioFileStreamParseBytes () #5 0x00000001915f7d98 in ___lldb_unnamed_symbol598$$MediaToolbox () What's going wrong here? Can anyone give me direction on what to fix? Or is FairPlay audio not even expected to work in Catalyst at this point?

I have an iPad app in which I'm starting to support multiple windows / scenes. I have one main window type, let's say MainScene, and at least one secondary window type for opening specific types of content, say DetailScene. I have not declared my scene types in Info.plist. I have implemented application:configurationForConnectingSceneSession:options: like this: -(UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options { NSUserActivity *activity = options.userActivities.anyObject; NSString *activityType = activity.activityType; if ([activityType isEqualToString:@"detailType"]) return [DetailSceneDelegate makeSceneConfiguration]; return [MainSceneDelegate makeSceneConfiguration]; } Say I perform these steps: Launch app for the first time. I get a call to configurationForConnectingSceneSession, and the activity type is nil so it returns a MainScene. Open a new window for some piece of content. That uses the detail scene activity type, so configurationForConnectingSceneSession returns a DetailScene. Creating the new scene looks like this: NSUserActivity *activity = [[NSUserActivity alloc] initWithActivityType:@"detailType"]; activity.userInfo = @{@"content_id": @(contentRowId)}; [[UIApplication sharedApplication] requestSceneSessionActivation:nil userActivity:activity options:nil errorHandler:nil]; Suspend the app and open the app switcher. Discard (by flicking up) first the main window and then the detail window. The app is now killed. Relaunch the app. At this point I do not get a call to configurationForConnectingSceneSession. I get the detail scene back, restored from its user activity, with calls straight to DetailSceneDelegate. My question: how do I control what scene gets restored in this situation? I want my main scene to come back. Messages and Mail and Notes all do this. If you open Messages and drag a conversation out into a new window, you get a window for that conversation with a Done button in the corner that will dismiss the window. If you perform my steps above with Messages, you will relaunch to the full Messages view. Are they converting the detail view to a main view on the fly? Or is there a way to tell the system that the detail scene is secondary and should not be restored first, or that I should get asked what I want to restore via configurationForConnectingSceneSession? Or something else?

As of iOS 14, UICollectionViewDiffableDataSource has a reorderHandlers property. It's demonstrated in some sample code and talked about in WWDC 2020 session on Advances in Diffable Data Sources. The presenter states that you have to provide a canReorder and didReorder closure to enable the feature. The sample code uses it in a collection view with a list layout configuration, and configures the list cells with reorder accessories. The canReorder and didReorder methods are called as expected. But if I remove the reorder accessories from the cells, reordering no longer works - it doesn't call either closure. It also doesn't work in my app, where I have a grid layout using a compositional layout. How do I enable reordering on UICollectionViewDiffableDataSource without list cells and reorder accessories?

I have a UICollectionView that I feed data into using UICollectionViewDiffableDataSource. I want to display a scroll scrubber on the trailing edge of it, like I'd get if I implemented the data source methods indexTitlesForCollectionView and indexPathForIndexTitle. But the data source is the diffable data source object, and there's no property or closure on it to supply index titles as of iOS 15. How are index titles supposed to work with UICollectionViewDiffableDataSource?

I notice in iOS 14 beta 4, collection views show index views on their trailing edge if the data source implements indexTitlesForCollectionView - https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/2851455-indextitlesforcollectionview?language=objc and indexPathForIndexTitle - https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/2851456-collectionview?language=objc. But I don't see a way to control any aspect of its appearance. On UITableView this shows up as the sectionIndexColor - https://developer.apple.com/documentation/uikit/uitableview/1614915-sectionindexcolor?language=objc property. Does this property exist on UICollectionView somewhere I didn't think to look? Or is it just not there (yet)? FB8284500

In the session on StoreKit 2 (which looks amazing!), the presenter says: In fact, if your app is running when a purchase is made on another device, you'll be notified about the new transaction. This seems to mean that when an app uses the listener API to be notified of transactions, it will get transactions that happened on other devices. My app offers purchases across other platforms in addition to iOS, and when a purchase happens we register it with our own account system. If a user has the app running on both their iPad and iPhone and makes a purchase on the phone, if the iPad gets notified of it the same way it would of a purchase made on the iPad, both devices will try to report it to our system. This seems undesirable. What's the recommended approach here? Should we just make sure our system will disregard duplicate transaction reports? Or is there a way to know whether a transaction originated on this device? I don't see a property on the transaction type that looks like it could accomplish this. Maybe the deviceVerification properties? But that's seems more like the new edition of transaction receipt verification - failing that check would presumably mean that the purchase is invalid, not that it didn't happen on this device...?