There are many units which are inverse of standard units, e.g. wave period vs Hz, pace vs speed, Siemens vs Ohms, ...
Dimension can be subclassed to create the custom units.
How to extend Measurement.converted( to: )?
I was looking at somehow using UnitConverter and subclass to something like UnitConverterInverse.
Thoughts?
General
RSS for tagDelve into the world of built-in app and system services available to developers. Discuss leveraging these services to enhance your app's functionality and user experience.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
I have applied for CarPlay support here Apply here to get your app approved for CarPlay use: https://developer.apple.com/contact/carplay/ but have not received any acceptance or answers. Does anyone know what to do?
I try to update remoteHandle using CXCallUpdate for outgoing call, but this works only on iOS 15 but not on 17 or 18 (16 didn't test). This problem actual only for outgoing calls, but for incoming calls update works fine.
func startOutgoingCall(with callID: UUID, userID: String) {
let handle = CXHandle(type: .generic, value: userID)
let action = CXStartCallAction(call: callID, handle: handle)
callController.requestTransaction(with: action) { [weak self] error in
// ...
}
}
func updateOutgoingCall(with callID: UUID, groupID: String) {
let update = CXCallUpdate()
update.remoteHandle = CXHandle(type: .generic, value: groupID)
provider.reportCall(with: callID, updated: update)
}
I also tried phoneNumber type but it seems initial handle that I set to CXStartCallAction not possible to change (value or even type).
I use this handle value to implement recall by tap on call in Recents tab of system address book. But since my calls can transform from p2p to group call, I need to update handle value or find some another way to pass call identification info.
When selecting a stroke path for object on PKCanvas, the option "Snap to Shape" appears.
I understand this function is still in beta and has not made available natively to other PencilKit app. Is there a way using Stroke API to call this function directly after the user hold pencil for half a second when stroke is done drawing, just like how it behaves in native apps?
App out of memory and killed by Jetsam event seems not report to MetricKit diagnostic, it only contains crash or watch dog kill (scene create or scene update).
So I want to ask to report these issues to MetricKit
Issue
After upgrading to Tahoe 26.2, print queues monitored by PaperCut no longer work. The print queue gets paused, and the jobs fail to print.
This issue was discovered during our internal testing prior to the Tahoe 26.2 public release, and a growing number of our mutual customers have also reported it since then.
Root cause
This appears to be due to changes in the behavior of CUPS Sandbox restrictions, which prevent the backend (and filter) from reading/writing to the PaperCut install folder.
Error messages
From syslog.
2025-12-22 16:41:59.283761+1100 0x1daf61 Error 0x0 0 0 kernel: (Sandbox) Sandbox: papercut(5783) deny(1) file-write-data /Library/Printers/PaperCut/Print Provider/print-provider.log
When trying to create a TCP socket from the PaperCut filter.
2025-12-15 19:50:08,403 ERROR: os_tcp_socket_create: getaddrinfo failed: nodename nor servname provided, or not known
Technical details
PaperCut implements print queue monitoring using a CUPS backend (and filter).
CUPS backends and filters run in a security 'sandbox' which limits what they can do (such as file/folder access, create network sockets, and execute sub-processes, etc.).
The PaperCut backend (and filter) relies on some of these operations, so to function correctly, our code updates /etc/cups/cups-files.conf with "Sandboxing relaxed".
Until 26.2, this relaxed mode allowed us to read/write to PaperCut folders, create TCP sockets to communicate with the local PaperCut Application Server, and execute/kill sub-processes.
As an alternative to the relaxed mode, we also tried "Sandboxing off", but that doesn't help either (from CUPS scheduler/conf.h).
typedef enum
{
CUPSD_SANDBOXING_OFF, /* No sandboxing */
CUPSD_SANDBOXING_RELAXED, /* Relaxed sandboxing */
CUPSD_SANDBOXING_STRICT /* Strict sandboxing */
} cupsd_sandboxing_t;
Test code
We can provide a simplified version of our backend that demonstrates the issue if required
Questions
Has the CUPS sandbox relaxing changed? According to the CUPS man pages (cups-files.conf(5)), "Sandboxing relaxed" should still work as before.
If this is the new intended behavior, what are the other options/directives we can use to relax the limitations on CUPS backends and filters?
General:
Forums topic: Family Controls
Forums tag: Family Controls
Configuring Family Controls documentation
Requesting the Family Controls entitlement documentation
Screen Time Technology Frameworks documentation
FamilyControls documentation
What's new in Screen Time API video
Meet the Screen Time API video
Topic:
App & System Services
SubTopic:
General
Tags:
Entitlements
Signing Certificates
Family Controls
Screen Time
On iOS 18 and lower version, my application supports automatically switching to [System settings - Personal Hotspot] directly. But on iOS 26, my application will be redirected to [System settings- Apps].
Does iOS 26 disable the behavior of directly jumping to the system hotspot page? If support, could you share the API for iOS 26?
We're building a parental control app using FamilyControls (.child authorization). Our architecture:
Parent sends pause command → Firestore + FCM
Child receives push → NotificationService Extension triggers main app
Main app sets ManagedSettings Shields
Problem: If child disables Notifications in Settings and force-quits the app, we cannot enforce Shields.
What we've tried:
Firestore Realtime Listener (works only when app is running)
DeviceActivityMonitor (intervalDidStart/End only triggers at schedule boundaries, eventDidReachThreshold requires explicit app selection via FamilyActivityPicker)
Question: Is there a recommended approach for parental control apps to reliably enforce Shields when the child has disabled notifications? Or is this a known limitation?
Topic:
App & System Services
SubTopic:
General
Tags:
Family Controls
Device Activity
Managed Settings
Screen Time
Hey there,
We are being incorrectly blocked by Time Limits since the iOS 26 update released earlier this year. We are receiving complaints from parents that set a screentime limit for "All apps", and then add an exception for us, that they are still getting blocked by the OS after a certain period of time. While we originally thought this was fixed in 26.1, we have recently been made aware it still occurs.
Has anyone else experienced this issue? Is there something we can do from our side to protect ourselves from this? Telling customers to remove their "All app" limit isn't really practical given our customer base, so we're looking to see if there's something on Apple's end or our end that can alleviate this.
Project Background:
I am developing a third-party custom keyboard for iOS whose primary feature is real-time voice input.
In my current design, responsibilities are split as follows:
1. The container (main) app is responsible for:
Audio recording
Speech recognition (ASR)
2. The keyboard extension is responsible for:
Providing the keyboard UI
Initiating the voice input workflow
Receiving transcription results via an App Group
Inserting recognized text into the active text field using textDocumentProxy.insertText(_:)
Intended User Flow
The intended workflow is:
The user is typing in a third-party app (for example, WeChat) using my custom keyboard.
The user taps a “Voice Input” button in the keyboard extension.
The keyboard extension activates the container app so that audio recording and ASR can begin.
After recording has started, control returns to the original app where the user was typing.
The container app continues running in the background, maintaining active audio recording and ASR.
Recognized text is continuously streamed back to the keyboard extension and inserted into the current cursor position in real time.
Observed Industry Behavior
Some popular third-party keyboards on iOS, such as WeChat Keyboard and Doubao Keyboard, appear to provide a similar user experience in which:
Voice input can be initiated directly from the keyboard while typing in another app.
The user remains (or returns) in the original typing context after voice input starts.
Speech recognition continues and text is streamed into the active text field without interrupting the typing experience.
I would like to better understand how this type of workflow aligns with iOS platform capabilities and supported APIs.
My Questions
Is it supported by iOS public APIs for a custom keyboard extension to activate its container app to start audio recording and ASR, then return to the original host app while the container app continues recording and performing ASR in the background?
If this workflow is not supported, are there any Apple-recommended or supported alternative architectures for achieving a similar user experience, especially when audio recording and ASR logic are currently implemented in the container app rather than in the keyboard extension?
Goal
My goal is to design a solution that is fully compliant with iOS public APIs and platform constraints, while providing a real-time voice input experience comparable to existing third-party keyboards on the platform.
Any guidance on supported APIs, recommended architectures, or relevant documentation would be greatly appreciated.
Text filtering: behavior of current message is affected by behavior of past message from same origin
If there is this situation:
A text message is sent from a sender and gets classified as junk (by a text filtering extension) with the result that it gets send to the spam folder as expected.
A text message with different content is sent from the same sender and gets classified as allowed, however it also gets sent to the spam folder.
If the above is repeated but after step 1 the message is deleted, then in step 2 the message doesn't get sent to the spam folder.
So the presence of the message from step 1 being in the spam folder is having an effect on the behavior of step 2.
Expected beahavour (if so, why?), or a defect?
I'm developing a proximity tool on macOS Tahoe 26.2 (M4 MacBook Pro) to detect when my iPhone leaves the immediate vicinity of my macbook.
Does NearbyInteraction on macOS support persistent background sessions for detecting peer absence (didInvalidate/timeout), or is CoreBluetooth still required as the keep-alive trigger?
Hi Apple Developer Community,
I'm implementing MetricKit launch performance tracking in our iOS app and need clarification on two properties:
histogrammedTimeToFirstDraw
histogrammedOptimizedTimeToFirstDraw
The Documentation Problem:
The official MetricKit documentation provides minimal explanation of these properties beyond their names. Based on naming conventions, I initially assumed:
histogrammedTimeToFirstDraw = cold launches
histogrammedOptimizedTimeToFirstDraw = warm/optimized launches
Based on our measurements:
The “optimized” metric appears only in a small fraction of launches
The "optimized" metric is actually slower
The naming suggests the opposite behavior
Questions:
What specific launch conditions does each metric measure?
Why would "optimized" launches be slower and less frequent?
Is histogrammedOptimizedTimeToFirstDraw related to iOS app pre-warming or prediction features?
If these metrics don’t correspond to cold vs. warm launch times, is there an alternative way to measure them accurately?
Any clarification from Apple or insights from developers who've tracked these metrics would be greatly appreciated.
Some Apple URL schemes are documented for third-party use. It’s fine to use those URL schemes for their intended purpose.
Other Apple URL schemes are not officially documented. Their use is unsupported. If you rely on such implementation details, things might work, or they might not, and that state might change over time.
IMPORTANT If you ship via the App Store, pay attention to clause 2.5.1 of the App Review Guidelines.
The Apple URL scheme documentation is not always easy to find. I’m aware of the following:
Apple URL Scheme Reference
QA1924 Opening Keyboard Settings from a Keyboard Extension [This Q&A was retired years ago.]
Preparing your app to be the default messaging app
The doc comments for es_new_client in <EndpointSecurity/ESClient.h>
Developer > Bug Reporting describes the applefeedback scheme
Additionally, as questions about this most commonly crop up in the context of opening Settings (System Settings on macOS), I wanted to highlight the following:
UIApplication.openSettingsURLString property (in Objective-C this is UIApplicationOpenSettingsURLString)
UIApplication.openNotificationSettingsURLString property (in Objective-C this is UIApplicationOpenNotificationSettingsURLString)
UIApplication.openDefaultApplicationsSettingsURLString property (in Objective-C this is UIApplicationOpenDefaultApplicationsSettingsURLString)
AccessibilitySettings.openSettings(for:) method
FIFinderSyncController.showExtensionManagementInterface() class method
SMAppService.openSystemSettingsLoginItems() class method
VSOpenTVProviderSettingsURLString global
CXCallDirectoryManager.openSettings(completionHandler:) method
SFSafariSettings.openExportBrowsingDataSettings() method
SFSafariSettings.openExtensionsSettings(forIdentifiers:) method
If your app needs to perform some action that’s not covered by the above, file an enhancement request for a supported way to do that. Make sure to describes your use case in detail.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Revision History
2026-01-07 Added a reference to the SFSafariSettings methods.
2025-10-28 Added a reference to UIApplication.openDefaultApplicationsSettingsURLString. Made other minor editorial changes.
2025-04-21 Added a reference to CXCallDirectoryManager.openSettings(completionHandler:).
2024-10-25 Added a reference to UIApplication.openNotificationSettingsURLString and VSOpenTVProviderSettingsURLString. Added a link to Preparing your app to be the default messaging app.
2024-10-01 Added info about the applefeedback URL scheme.
2024-09-29 Added a reference to SMAppService.openSystemSettingsLoginItems().
2024-09-27 Added a titbit for Finder Sync extension developers. Added an invitation to file feedback.
2024-08-05 First posted.
iOS Intermittent Bug: UserDefaults Preferences Loading Issue
Problem Summary
We're experiencing an intermittent issue where UserPreferences.shared.preferences returns inconsistent values even after calling getPreferences(). The behavior is unpredictable and affects critical functionality.
Environment
iOS Version: 15+
Language: Objective-C with Swift interop
Storage: UserDefaults with App Group (group.com.jci.tyco.glss)
Architecture: Singleton pattern for UserPreferences (Swift class)
The Issue
When a push notification arrives and triggers the showEvent: method, user preferences are sometimes loaded correctly and sometimes return nil or default values:
Scenario A (Works - ~60% of time):
Scenario B (Fails - ~40% of time):
Observed Pattern
From extensive logging over multiple test runs:
Key Observation:
At app launch: Preferences often load successfully
Seconds later when push arrives: Same preferences become unavailable
User navigates to another screen and back: Preferences suddenly work again
Code Structure
Objective-C AppDelegate.m
- (void)showEvent:(FMEvent *)event eventReadSource:(FMEventReadSourceType)eventSource {
BOOL isUserRoleEndUser = [[FMUserRolesRepository instance] userRoleAvailable:FMUserRoleEndUser];
UserPreferences *userPrefs = [UserPreferences shared];
[userPrefs getPreferences]; // ← Called here
// Immediately after, sometimes nil!
bool hasFireAudio = [userPrefs.preferences.fireAudio.lowercaseString isEqual:@"true"];
NSLog(@"isUserRoleEndUser: %d | Fire Audio: %d", isUserRoleEndUser, hasFireAudio);
// Decision logic based on preferences
if ([FMConstants getUserRegion] == UserRegionUK &&
isUserRoleEndUser &&
userPrefs.preferences && // ← Sometimes nil here
hasFireAudio) {
// Show Screen A
} else {
// Show Screen B
}
}
```class UserPreferences: NSObject {
static let shared = UserPreferences()
var preferences: FMUserPreferencesInfo? // ← This becomes nil intermittently
func getPreferences() {
let userDefaults = UserDefaults(suiteName: "group.com.jci.tyco.glss")
if let data = userDefaults?.data(forKey: "UserPreferences") {
// Decode and set preferences
self.preferences = // decoded object
} else {
// Create default preferences with fireAudio = "false"
self.preferences = FMUserPreferencesInfo()
}
}
}
Hello,
Back in January 2024, I filed a bug report regarding a cache being kept by the macOS Wallpaper Agent. This cache contains every image ever set as a users wallpaper, and at the time the issue was reported, it never cleared, leaving hundreds of gigabytes wasted on users disks in some cases.
FB13536275
This issue was ultimately fixed in macOS 15.1 beta 6, and remained fixed for the duration of macOS 15. The fix was excellent - the cache was reduced to storing just 2-3 days worth of images.
Sadly, we've discovered that this issue is back in macOS Tahoe. The cache has moved locations, and once again is not clearing. We have filed this bug again, less than a year after it was first fixed:
FB20636593
We develop an app called 24 Hour Wallpaper that keeps the wallpaper in sync with the time of day. This necessitates that the app regularly changes the wallpaper, which sadly now results in an infinitely growing and useless cache of BMP files generated by the system.
As we waited 10 months for this to get fixed the first time, we expect to wait at least that long to get it fixed again, and have no confidence that it will stay fixed because the last fix lasted less than a year. This leaves us in a bad position, as people can't use our app without the cache growing arbitrarily and ultimately completely filling their disk.
We've already had customers call Apple to complain about this, and the good news is that the support agents understand that this is a problem with macOS, not with our app.
What we've decided to do is add a feature to the app that monitors the size of this cache and periodically deletes it. We're required to get the users permission the first time to do this, but after that the permission is cached, so the app can keep the cache folder clean regardless of if macOS is doing it's job or not.
We haven't seen any side effects or problems as a result of doing this. We've seen other apps like CleanMyMac do this without any problems. We're wondering if there is anything we should be aware of regarding this caches behavior before releasing this flushing feature.
Thanks for your time,
-josh
Hello,
Recently we got a question about the keyboard sensor data collection in our research project:
"For the typing statistics, was any typing included or only messaging and notes? E.g., typing in the browser, phone search, calendar, etc?"
While I believe it should be any typing included, I was not able to find a document explicitly stating that. Could you help to confirm it or guide me to any documentation explaining it?
Thanks!
I'm building a voice-to-text keyboard extension that needs to open the main app briefly for audio recording (since keyboard extensions can't record audio), then return the user to their original app.
The flow I'm trying to achieve:
User is in WhatsApp (or Messages, Slack, etc.)
User taps "Voice" button in my keyboard
My main app opens via deep link (myapp://keyboard/dictation)
App starts recording
App automatically returns user to WhatsApp
I cannot find a way to detect which app the keyboard is running inside, or which app opened my main app via the deep link.
UIInputViewController.textDocumentProxy - No host app information available
UIApplication.OpenURLOptionsKey.sourceApplication in application(_:open:options:) - When opened from a keyboard extension, does this return the host app bundle ID or the keyboard extension bundle ID?
Private APIs (for research only, not production):
_hostBundleID on UIInputViewController - blocked/returns nil on iOS 18
KVC approaches - all blocked
Hardcoded app support - Works but requires maintaining a list of popular apps and showing multiple buttons instead of a single "Voice" button
My questions:
When a keyboard extension triggers a URL open (via SwiftUI Link or UIApplication.shared.open), what does sourceApplication contain? The host app or the keyboard extension?
Is there any supported way for a main app to know which app it was launched from, specifically when that launch originated from a keyboard extension?
How do apps like "Wispr Flow" achieve seamless return-to-app with a single voice button? They seem to auto-return to whatever app the user was in.
Environment:
iOS 18.0+
Xcode 16
SwiftUI keyboard using KeyboardKit
Any guidance on the recommended approach would be greatly appreciated. I understand there may be privacy reasons for limiting host app detection, but the UX of requiring users to manually swipe back (or tap app-specific buttons) is significantly worse than automatic return.
Install both Motiv Audio and Motiv Video apps from the App Store.
Open and use the Motiv Audio app. Remove audio app from background.
Open Motiv Video app.
Observe that the Motiv Audio app crashes.
Both apps are checking Free available space.
Both app are using Audio Engine
Topic:
App & System Services
SubTopic:
General