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Why Xcode 12.5 errs when using Class as a key in NSDictionary?
I downloaded Xcode 12.5 Beta and now an existing project does not compile with errors telling I can't use Class as a key in NSDictionary. Cannot initialize a parameter of type 'id<NSCopying>  _Nonnull const __unsafe_unretained' with an rvalue of type 'Class' I have assumes so far that while Class does not conform to NSCopying, it is safe to use as a dictionary key because it implements copy and copyWithZone:. Did anything change with that regard in the compiler/runtime shipped with Xcode 12.5? Is it safe (and endorsed practice) to cast to id<NSCopying> to silence these errors?
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4.3k
Jun ’21
isPressed is not reliable when Button is inside ScrollView
I opened a feedback ticket (FB16508762) but maybe someone in the community already found a workaround while the feedback reaches the maintainers. When I put a Button inside a ScrollView, the tap animation stops working reliably and works only when the user taps and holds the button for a short time. The reasons, I believe is related to the fact that isPressed of configuration does not change and the default button styles use it to animate the tap. import SwiftUI struct DebuggingButtonStyle: ButtonStyle { func makeBody(configuration: Configuration) -> some View { configuration.label .onChange(of: configuration.isPressed, { oldValue, newValue in print("Is pressed: \(oldValue) -> \(newValue)") }) } } struct ContentView: View { var body: some View { VStack { Text("Buttons inside scroll view respond to taps as expected, however isPessed value of the configuration do not change unless the user press and hold it. Try to press the promiment button quickly or use the debug button and observe the console log.") ScrollView { VStack { Button("Button Inside ScrollView") { print("Button tapped") } .buttonStyle(.borderedProminent) Button("Button Inside ScrollView (printing isPressed)") { print("Button tapped") } .buttonStyle(DebuggingButtonStyle()) } } .border(FillShapeStyle(), width: 2) Spacer() Text("For reference, here is a button outside of a ScrollView. Tap the promiment button to observe how the button is expected to animate in respnse to a press.") VStack { Button("Button Outside ScrollView") { print("Button tapped") } .buttonStyle(.borderedProminent) Button("Button Outside ScrollView (printing isPressed)") { print("Button tapped") } .buttonStyle(DebuggingButtonStyle()) } } .padding() } }
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420
Feb ’25
Phased release of a version while the previous phased release is not finished
I was not able to find info regarding this situation in the official docs. What will happen if a version was not yet released to all, and a new version is phased released? For example if I am phased releasing version 2.0. On day 3, when only 5% of the users have this version, I discovered that this version has a bug. I paused the release of 2.0 and created a hotfix version 2.1. What will happen all the users who did not receive 2.0 when I start phased release of 2.1? Will they get an immediate update to 2.0 or will they skip this version?
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791
May ’23
How to write AVAudioBuffer to a file?
If the audio buffer is AVAudioPCMBuffer, it is possible to write it into a file using AVAudioFile's writeFromBuffer:error: method. How should plain AVAudioBuffer be handled? In my specific case, I get this buffer from the callback of AVSpeechSynthesizer's writeUtterance:toBufferCallback: In fact the documentation says: // Use this method to receive audio buffers that can be used to store or further process synthesized speech. // The dictionary provided by -[AVSpeechSynthesisVoice audioFileSettings] can be used to create an AVAudioFile. - (void)writeUtterance:(AVSpeechUtterance *)utterance toBufferCallback:(AVSpeechSynthesizerBufferCallback)bufferCallback API_AVAILABLE(ios(13.0), watchos(6.0), tvos(13.0), macos(10.15)) ; But I don't know how exactly AVAudioFile can be used if the buffer is not guaranteed to be an AVAudioPCMBuffer.
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1.8k
Sep ’21
Is it safe to put AVAudioSession calls not on main thread?
We have noticed that sometimes our app spends too much time in the first call of AVAudioSession.sharedInstance and [AVAudioSession setCategory:error:] which we call on app's initialization (during init of apps delegate). I am not sure if the app is stuck in these calls or it simply takes too much time to complete. This probably causes the app to crash due to main thread watchdog. Would it be safe to move these calls to a separate thread?
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2.7k
Jan ’22
How to deduce from NSMethodSignature that a struct argument is passed by pointer?
How to deduce from NSMethodSignature that a struct argument is passed by pointer? Specifically on ARM. For example if I have: @protocol TestProtocol <NSObject> - (void)time:(CMTime)time; - (void)rect:(CGRect)point; @end And then I do: struct objc_method_description methodDescription1 = protocol_getMethodDescription(@protocol(TestProtocol), @selector(time:), YES, YES); struct objc_method_description methodDescription2 = protocol_getMethodDescription(@protocol(TestProtocol), @selector(rect:), YES, YES); NSMethodSignature *sig1 = [NSMethodSignature signatureWithObjCTypes:methodDescription1.types]; NSMethodSignature *sig2 = [NSMethodSignature signatureWithObjCTypes:methodDescription2.types]; const char *arg1 = [sig1 getArgumentTypeAtIndex:2]; const char *arg2 = [sig2 getArgumentTypeAtIndex:2]; NSLog(@"%s %s", methodDescription1.types, arg1); NSLog(@"%s %s", methodDescription2.types, arg2); The output is: v40@0:8{?=qiIq}16 {?=qiIq} v48@0:8{CGRect={CGPoint=dd}{CGSize=dd}}16 {CGRect={CGPoint=dd}{CGSize=dd}} Both look similar, no indication that CMTime will be actually passed as a pointer. But when I print the debug description: NSLog(@"%@", [sig1 debugDescription]); NSLog(@"%@", [sig2 debugDescription]); The first prints: ... argument 2: -------- -------- -------- -------- type encoding (^) '^{?=qiIq}' flags {isPointer} ... While the second prints: ... argument 2: -------- -------- -------- -------- type encoding ({) '{CGRect={CGPoint=dd}{CGSize=dd}}' flags {isStruct} ... So this information is indeed stored in the method signature, but how do I retrieve it without parsing the debug description? Are there rules I can use to deduce this myself? I tried to experiment with different structs but it is hard to spot a pattern.
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1.5k
Jan ’22
Is it possible to obtain the clipping path of CGContext?
There is no API to create an intersection between two CGPaths, however CoreGraphics knows how to do it behind the scenes. When calling CGContextClip (link) it will intersect current and clipping paths and store it in the clipping path. I was thinking to utilize this to perform intersections between paths I have. The problem is I can not find a way to retrieve back the clipping path from CGContext. Am I correct that such API does not exist or did I miss something?
3
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1.8k
Aug ’22
Does scheduling a price change of a subscription affect existing subscribers?
This is a followup question to this document: https://developer.apple.com/help/app-store-connect/manage-in-app-purchases/schedule-price-changes If we schedule a price change for a subscription product, will it affect existing subscribers in their next billing period? How will they be notified that this change happened?
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1.3k
Mar ’23
Is it possible to cancel a subscription for all users who already own it?
We are adding an feature in the app and we want to sell a special subscription for the app which lets users use the feature. We might want to stop supporting this feature and remove it from the app in the future. Not just stop selling the subscription, but completely get rid of the feature in future version of the app. Once the feature is removed, the users who bought the special subscription, will not be able to access the feature and they will receive the same experience as users who bough a normal subscript we are currently offering. What is the best approach to deal with this situation? Is it possible to force cancelation of this product or changing auto renew to off for all users who are subscribed to it? Is it possible to force downgrade/upgrade of that product for all users who are subscribed to it? Are we stuck with supporting this feature forever, or is there a best practice which will allow us to phase it out?
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1.2k
Mar ’23
How do the run loop of the main thread and the main queue are related?
Do run loops use an operation queue under the hood? When I dispatch to the mian queue, I know it will run on the mian thread, which means it will be handled b the main thread's run loop. But is the other way around correct? More specific question, is it possible somehow that the following code will return true? OperationQueue.current != OperationQueue.main && Thread.isMainThread I tried to do for example to dispatch to the main thread using a timer. myQueue.sync { let timer = Timer(timeInterval: 1, repeats: false) { _ in let curr = OperationQueue.current let main = OperationQueue.main print("\(String(describing: curr)) \(main)") } RunLoop.main.add(timer, forMode: .common) } And got the same pointer. But maybe some other way of dispatching to the main run loop will give different results, possibly that is why OperationQueue.current can return nil.
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2.1k
May ’23
How to make changes of text in search filed to cause animated changes in the view?
Following the examples from the official documentation: https://developer.apple.com/documentation/swiftui/adding-a-search-interface-to-your-app When the user types in the text in the search field, the list is updated with filtered results. How do I cause these changes to be animated? I tired to put .animated() after the .searchable modifier, the result was what I am looking for, however it also broke the animation of the search field getting/releasing focus.
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505
Oct ’24
Widget Extension Jetsamming when Loading SVG Images
To reproduce: Create a new standard iOS project and add a Widget extension to it. Download an SVG from here: https://pixabay.com/vectors/flourish-decorative-ornamental-3166119/ Add the SVG asset into Assets.xcassets. Replace the line Text(entry.date, style: .time) with Image("flourish-3166119").frame(width: 20). When running the extension, I get Thread 1: EXC_RESOURCE RESOURCE_TYPE_MEMORY (limit=30 MB, unused=0x0). Notice that the asset is only 8k but something in the rendering of the SVG into bitmap cause a memory spike. I tested this with Xcode 13.0, iOS 14.4.1 Xs MAX device. Is there a way to overcome this, or should I dump SVG and pre render the images for x2 and x3 scale factors and call it a day? Edit: Just to clarify, the issue happens with only 1 entry as well. I attached the full source for reference. Demo convenience:
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1.6k
Jan ’22
How to handle events by a view and then pass them to the view directly below?
I am trying to implement my own version of UIMenuController. One of the things I am struggling to imitate is what happens when a there is a touch event outside the menu. In this case the menu will be dismissed, but the event will also be passed to the correct view . So I need somehow to handle or capture the event in the menu or some transparent view covering the whole screen but also let it pass to the view below it. One idea is to override hitTest:withEvent: of the menu view, dismiss the menu when it is called (if point is outside the menu) and then return nil as if it was transparent to events. The issue is that hitTest:withEvent: must be pure function without side effect. On other hand, when touchesBegan:withEvent: is called, it is possible dismiss the menu and to pass the event to the nextResponder, but the view directly below the menu is not necessarily the superview of the menu view, so it is not part of the responder chain.
Topic: UI Frameworks SubTopic: UIKit Tags:
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868
Oct ’21