I'm trying to send my app silent push notifications by setting the "content-available" flag to 1 in the notification payload. This works, but there is a problem: if my app is not running in the foreground, the notification is visible on the home screen. I don't want this: I just want the app to see it, without waking up the screen or alerting the user. If the app is open when the notification comes in, it works as expected; I receive the notification inside my app, and iOS does not display any alert or banner. I configured my app with the "Remote Notifications" background mode. What am I doing wrong?

I can't get my latest iPhone app to run in portrait mode only. In Xcode I've checked only the box that says "Portrait" under Device Orientation, and I've also examined the Info.plist file to ensure that there aren't any hidden settings for other orientations. I've also tried checking or un-checking iPad, and checking "Requires Full Screen" when that option appears. No matter what I do, when I run the app on my phone and rotate the screen, the interface rotates. What am I doing wrong?

I've got an iOS project that I've been working on for some months. Just recently, I started seeing a compiler error to the effect that "Referencing instance requires that X conforms to Equatable". It shows up in places where you'd expect something to be Equatable, such as the argument to firstIndexOf: on an array. The class in question is written in Swift, but descents from an Objective-C base class. I know there are some issues with how Equatable interacts with Obj-C but I think I've done it right. The base class extends NSObject, and the subclass implements both the isEqual function and the static == function. (I don't think the latter is necessary but I included it just in case). I've tried explicitly including "Equatable" in the definition of the subclass but the compiler rejects this as "Redundant conformance to protocol". I'm not exactly sure how that works since NSObject doesn't extend Equatable but I guess Swift considers them equivalent. Here's where things get super weird though. Xcode still builds and runs the project despite the compiler error, and the code runs, and it works. I even put a breakpoint in the isEqual function to make sure it was getting called. Also, when I clean and rebuild the project, the compiler error often disappears for some time, reappearing hours or days later. So I think this must be some kind of bug in Xcode or Swift itself. What do you think? Frank

Views A and B are equal in width (set up via a constraint). The actual width will vary at runtime. What I want to do is arrange view A such that it is horizontally centered on B but offset to the left by 1/10th of the total width. In other words, if views A and B were 100 units in length, I'd want A to be positioned 10 units to the left of B. If the width were 150 units then the A position would be 15 to the left, etc. I thought I could do this with either a leading constraint or a centerX constraint using a multiplier of 0.9, but it isn't working out the way I want. What's the best solution?

Do string functions such as "replacingOccurrences" and "trimmingCharacters" always return a new string, even if the old string did not need to be modified? In other words -- if I'm doing a large number of "replacingOccurrences" in my app but only a small number of the strings actually contain the sequence I want to replace, should I check to see if the sequence exists before calling replacingOccurrences, in order to avoid an unnecessary string allocation? I would guess that Swift would return the same string if it didn't require any modifications, but the documentation just says "Returns a new string". Thanks, Frank

I'm getting the dreaded "Failed to prepare the device for development" error when I connect my iPhone running iOS 15 to the latest version of Xcode. I've tried rebooting both devices. How do I fix this?

Is there any way an account owner can authorize a different user to accept updated license agreements? I manage multiple apps on behalf of customers, most of whom fail to accept these agreements until the day they need me to publish a new app and I have to hunt them down and ask them to do it. If it were one or two customers it wouldn't be a big deal, but I have nearly 40 of them, and this happens several times per year. It's a major hassle.

I often get crash logs where nothing in the stack trace is my code, other than an entry point in main. I don't know how to use these to figure out where the problem is. For example this one, Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Triggered by Thread: 0 Last Exception Backtrace: 0 CoreFoundation 0x1c21cf180 __exceptionPreprocess + 228 (NSException.m:172) 1 libobjc.A.dylib 0x1c13a79f8 objc_exception_throw + 56 (objc-exception.mm:557) 2 UIKitCore 0x1ee572b1c -[UINavigationController pushViewController:transition:forceImmediate:] + 2312 (UINavigationController.m:7317) 3 UIKitCore 0x1ee5720b0 -[UINavigationController pushViewController:animated:] + 664 (UINavigationController.m:7272) 4 UIKitCore 0x1ee62ae9c -[_UIViewControllerTransitionCoordinator _applyBlocks:releaseBlocks:] + 264 (UIViewControllerTransitioning.m:1121) 5 UIKitCore 0x1ee62725c -[_UIViewControllerTransitionContext _runAlongsideCompletions] + 140 (UIViewControllerTransitioning.m:374) 6 UIKitCore 0x1ee626f34 -[_UIViewControllerTransitionContext completeTransition:] + 132 (UIViewControllerTransitioning.m:286) 7 UIKitCore 0x1ee6371f4 __53-[_UINavigationParallaxTransition animateTransition:]_block_invoke.118 + 740 (_UINavigationParallaxTransition.m:393) 8 UIKitCore 0x1ef032d1c -[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 752 (UIView.m:12852) 9 UIKitCore 0x1ef009a74 -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 312 (UIView.m:0) 10 UIKitCore 0x1ef00a048 -[UIViewAnimationState animationDidStop:finished:] + 296 (UIView.m:2111) 11 UIKitCore 0x1ef00a0e8 -[UIViewAnimationState animationDidStop:finished:] + 456 (UIView.m:2130) 12 QuartzCore 0x1c671f3c8 CA::Layer::run_animation_callbacks(void*) + 284 (CALayer.mm:6680) 13 libdispatch.dylib 0x1c1c0d7d4 _dispatch_client_callout + 16 (object.m:511) 14 libdispatch.dylib 0x1c1bbb008 _dispatch_main_queue_callback_4CF$VARIANT$mp + 1068 (inline_internal.h:2441) 15 CoreFoundation 0x1c2160b20 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12 (CFRunLoop.c:1813) 16 CoreFoundation 0x1c215ba58 __CFRunLoopRun + 1924 (CFRunLoop.c:3113) 17 CoreFoundation 0x1c215afb4 CFRunLoopRunSpecific + 436 (CFRunLoop.c:3247) 18 GraphicsServices 0x1c435d79c GSEventRunModal + 104 (GSEvent.c:2245) 19 UIKitCore 0x1eeba7c38 UIApplicationMain + 212 (UIApplication.m:4353) 20 therapeutic-listening 0x100b83380 main + 88 (main.m:16) 21 libdyld.dylib 0x1c1c1e8e0 start + 4 (:-1) Thread 0 name: Thread 0 Crashed: 0 libsystem_kernel.dylib 0x00000001c1d6b0dc __pthread_kill + 8 (:-1) 1 libsystem_pthread.dylib 0x00000001c1de4094 pthread_kill$VARIANT$mp + 380 (pthread.c:1492) 2 libsystem_c.dylib 0x00000001c1cc3ea8 abort + 140 (abort.c:94) 3 libc++abi.dylib 0x00000001c1390788 abort_message + 132 (abort_message.cpp:75) 4 libc++abi.dylib 0x00000001c1390934 default_terminate_handler() + 308 (cxa_default_handlers.cpp:68) 5 libobjc.A.dylib 0x00000001c13a7e00 _objc_terminate() + 124 (objc-exception.mm:693) 6 libc++abi.dylib 0x00000001c139c838 std::__terminate(void (*)()) + 16 (cxa_handlers.cpp:66) 7 libc++abi.dylib 0x00000001c139c8c4 std::terminate() + 84 (cxa_handlers.cpp:97) 8 libdispatch.dylib 0x00000001c1c0d7e8 _dispatch_client_callout + 36 (object.m:514) 9 libdispatch.dylib 0x00000001c1bbb008 _dispatch_main_queue_callback_4CF$VARIANT$mp + 1068 (inline_internal.h:2441) 10 CoreFoundation 0x00000001c2160b20 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12 (CFRunLoop.c:1813) 11 CoreFoundation 0x00000001c215ba58 __CFRunLoopRun + 1924 (CFRunLoop.c:3113) 12 CoreFoundation 0x00000001c215afb4 CFRunLoopRunSpecific + 436 (CFRunLoop.c:3247) 13 GraphicsServices 0x00000001c435d79c GSEventRunModal + 104 (GSEvent.c:2245) 14 UIKitCore 0x00000001eeba7c38 UIApplicationMain + 212 (UIApplication.m:4353) 15 therapeutic-listening 0x0000000100b83380 main + 88 (main.m:16) 16 libdyld.dylib 0x00000001c1c1e8e0 start + 4 (:-1)

I'm working on a screen where the goal is for the user to walk for 6 minutes while the app times them and measures the distance walked. I'm using CMPedometer to track the walking distance and a repeating 1-second Timer to count down the time. This works fine as long as the app is in the foreground, but I'd like my user to be able to lock their phone and put it away while they walk. I used UIApplication.shared.beginBackgroundTask, but it doesn't provide enough time. It usually only gives me around 30 seconds. I also tried calling UIApplication.shared.beginBackgroundTask again or calling it once every time the timer ticks, with no better result. How can I accomplish my goal here?

My company did an app for a customer 10 years ago. The app has in-app purchases (not subscriptions). It is an Objective-C code base. Over the years we've done minor updates to this app in order to keep it in compliance, but no major overhaul. The app has been pretty reliable in the past, but recently my customer is getting a flood of complaints from users who say their in-app purchases disappear and can't be restored. It's happening too often to just be a case of bad internet connection or similar issue. The only thing that seems to be consistent is that it's never US-based users. Whenever I test this app using sandbox accounts, I cannot reproduce the problems that are being reported. I'm always able to make purchases and restore them after reinstalling the app, or restore them to a different device. The content associated with the purchases always downloads correctly, even if I intentionally interrupt and restore internet access. What can I do to figure this out? Should an IAP based app from 2014 be expected to work correctly today? Are there new legal issues with non-US app stores that we need to be aware of? I realize there isn't a lot to go on here, but I don't have any more information. Thanks, Frank

If I'm talking to a Bluetooth (BLE) device using the Core Bluetooth functions, and I need to send or receive multiple packets (such as if I need to communicate a large message) is it guaranteed that the packets will arrive in the same order they were sent?

I have a customer who wants to protect the REST API of their app with a private certificate. They would then distribute the client certificate to the authorized users. Their app would not work unless the client certificate is already installed on the user's phone before they run the app. I have never done this before. Is it possible to install a client certificate on an iPhone without running an app, for example if it were sent in an email message? And if it is possible, is App Review going to let such an app into the app store? Thanks, Frank

I have an extremely straightforward situation where an @IBOutlet in a ViewController is connected to a property in an XIB file. I've been working with iOS apps for more than ten years, and done this about a million times. For some reason, the property becomes nil at some point after the view is loaded. I can check with the debugger to see that it is not nil at viewDidLoad, and there is nothing in my code that sets it to anything else. I added a custom setter and getter to the variable so that I could stop in the debugger when it gets set, and the setter only gets called once, with a non-nil value. I suspect that somehow, a different copy of my ViewController is getting instantiated, but when it does, there are no calls to any of the usual methods like viewDidLoad. In fact there is not even a call to the init method. I don't understand how this is possible.

Whenever I make a new app I end up getting bug reports from people who say they can't see text, or they can just about see white text against an almost white background. It always turns out to be because their phone is in dark mode, which I don't use. Almost all of my views have the background color set to "System background color" which is the default value when you create a view. Why does dark mode change the color of the text but not the background?

I'm setting up Auth0 to work with my app according to their instructions. I need to add an associated domain, but it doesn't work. When I try to use Auth0, it returns a message that says "Application with identifier (my-bundle-id) is not associated with domain (my-auth0-domain)". In Signing & Capabilities, I have the Associated Domains capability set up with this domain: "webcredentials:(my-auth0-domain)". I also added another version with ?mode=developer on the end of it, but neither works. I am sure that the domain I'm using is correct because I'm able to use it in Postman to authenticate with Auth0. I checked everything else against their documentation and samples several times.