Hi, I'm working with a BLE device manufacturer on a new device for which I'm tasked with developing the iOS app. The hardware developer told me: "In response to a Scan request (from a phone or other device) the BLE stack is configured to include a device identifier". The device identifier is something I need to see in the advertising packet before I connect to the device. I don't know what a "Scan request" is. Is this something I have to specifically ask for in my app? Is it something iOS does automatically? Thanks, Frank

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?

I want to customize or limit the typing suggestions for a UISearchBar input to a list of known words that exist within the material that is being searched. How is this done? Thanks, Frank

How do I disable the predictive text feature (word suggestions) of the keyboard when used with a UISearchBar?

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?

I'm trying to save a Dictionary to UserDefaults. My Dictionary is defined as [String:Data]. Since both String and Data are property objects, I expected this to work, but it doesn't: my app blows up with a "this class is not key-value coding compliant" error. Is this a bug, or am I doing something wrong?

Hi, My customer wants to do the thing where an app store URL is advertised which contains a referral code. When a user follows the link, it should take them to the app store to install the app, and then when the app is installed, it should be able to get access to the referral code in the original URL. I know such a thing was possible at one time because I remember talking to some of my colleagues about it, but I have never done it myself and whatever my coworkers did 8 years ago in Objective-C probably doesn't work anymore. Can someone let me know how to do this, or at least, let me know what the correct name for this procedure is so I can look it up? Thanks.

I have a table cell containing a UITextView. The table is using automaticDimension for the cell height and the cell itself is formatted in a way that the UITextView can be a variable height. The intention is that the textview and the cell should reisize as the user types and the text flows into additional lines. If I do nothing else, this doesn't happen. If I add a UITextViewDelegate and call sizeToFit() on the textview whenever the text changes, and then reload the table cell, it does resize, but it does so in an extremely sloppy and unusable way. Specifically, the textview loses focus, the cursor disappears, and the text starts to render in odd ways with overlapping characters or graphics from surrounding elements. What is the correct way to accomplish this? Thanks, Frank

I'm working on a BLE app with a hardware partner using samples of their device, which I am able to erase and re-flash when needed. When I try to use the device it initially works fine. I can connect to it, make requests, and get back responses. However, after a short time and a few successful runs, I start getting the error "Encryption is insufficient". The error is seen in the "didUpdateValueFor" function. I can still connect to the device, and enumerate all of its services and characteristics, but I can't read any data. If at this point I re-flash the device and also go into the iOS setting app and "forget" it, then I can use the device normally again, at least for a while. What causes this? Is there a way I can fix it in my app? Thanks, Frank

I manage several different apps for different customers, who have invited me as a user to their Apple Developer accounts. This week a new customer invited me and I accepted the invitation. If I go to App Store Connect, I can select that customer, view the Users screen and see that he has given me Admin access which is what I requested. However, when I go to developer.apple.com/account, I cannot access the "Certificates, IDs & Profiles" section. In fact, I do not even see the new customer in the pick list underneath my name. This customer is non-technical and needs me to do everything involved with publishing his app, starting with creating the App Store listing and certificates. In App Store Connect I can "Add App" but there are no bundle IDs in the pick list. If I click the link that says "Register a new bundle ID" it takes me to the Certificates page but with a different customer's account selected. Why am I unable to do this given that I have Admin access? Is there some other way I can set up this app? Frank

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 building a physical therapy app and as part of it, I want the app to oversee and measure certain exercises that the user will do. I'm not sure if I should use Core Motion, location services, or something else. These are the specific things we want to measure: The user walks for 6 minutes. At the end of it, we tell them how far they walked. The user runs for 30 seconds. We tell them their average speed and peak speed. The user does a broad jump: basically just jumping forward as far as they can. We want to measure the distance jumped. I'm thinking location services might work for #1 but I doubt it will be accurate enough for #2. For #3 I thought I could do this with the accelerometer if I took readings at short intervals and combined them with something like the trapezoidal rule, but I can't get this to produce a reliable result. Let me know what you think, thanks.