I happen to have a lot of experience writing a Windows application in c#, where the async/await pattern has been a standard feature for years. I can say from this experience that it's a great way to handle concurrency and I'm really happy that Apple is bringing this to Swift. I'm often critical of language improvements that end up reproducing things you could already do with a different syntax, but in this case it's definitely worth it. If you've never used async/await, it may initially look confusing. It looks like all you're doing is blocking your thread from running until another thread completes, but what really happens is that your thread returns at the point where the await keyword appears, and then resumes later when the result is available. So if your thread is the main thread, which is the most common case, using await doesn't block the main thread. Exactly how the compiler manages to suspend and resume the thread without destroying your local variables, I don't know, but I'm sure they figured out a way that makes sense. Frank

I've got a fairly old app that I first built back in 2014, and have been maintaining over the years. One of the screens in the app uses the camera to scan barcodes. The barcodes we scan are printed on labels, and are in the org.iso.Code128 format. When the app was first developed, I simply set the metadataObjectTypes property of AVCaptureMetadataOutput to all available types. This worked fine. The app scanned our barcodes very quickly with almost no issues. In 2017, we started seeing issues where barcode scanning was becoming slower. I reasoned that having it configured to scan for every possible barcode format might be the issue, so I went in and changed the code to have it scan only for the org.iso.Code128 format. This helped, for a while. Now, we're seeing the problem again in iOS 14 devices. On some devices it is nearly impossible to scan the barcodes. On others, you have to wait 20 or 30 seconds before the barcode is recognized. What could be causing this issue?

My app has been reporting error code -1200, "NSURLErrorSecureConnectionFailed", on a very small number of end user devices. I cannot reproduce the error. The devices that report this error have ranged from very old iOS 9 devices to modern iOS 14 devices. The documentation says, "An attempt to establish a secure connection failed for reasons that can’t be expressed more specifically." Can anyone elaborate on what kinds of reasons might cause this error? I'm otherwise stuck, with no way to explain this to my customers and no advice for how they might fix it. Thanks, Frank

How do I configure an iPad app to only work in portrait mode?In Xcode there are checkboxes for the four orientations, and only Portrait is checked, but the app still rotates into landscape mode.I also tried checking the "Requires full screen" box, but this didn't have any effect.Thanks,Frank

We have an auto-renewable subscription in our app that we want to stop offering. However, we want to make sure that people who have already purchased the subscription remain subscribed until the end of their current subscription period (and are subsequently unsubscribed and not charged further). What is the right way to do this?We tried submitting the app with the subscription still enabled in App Store Connect but hidden in the app, and our update was rejected because the reviewer couldn't find a way to subscribe.Thanks,Frank

A customer added me to their team today as a developer.When I sign in to App Store Connect, I can see and select their team from the list that appears under my name. However, when I open Xcode, the team doesn't appear under my Apple ID in Account Preferences or in the Team drop-down in the signing tab.I also noticed that even though I can select the team in App Store Connect, my name doesn't appear on the Users and Access screen. But I can see the app that I was assigned to work on.I tried closing and opening Xcode several times. I also removed and re-added my Apple ID.I waited several hours in case this was some sort of data propagation issue, but it hasn't resolved. What should I do next?Frank

Hi,The UIWebView class has a convenient property called scalesPageToFit, which can be used to allow small web pages to scale automatically to fit the frame of the web view.But this class is now deprecated in favor of WKWebView, which doesn't seem to have an equivalent property. How do I get the same functionality with WKWebView?Thanks,Frank

Hi,I'm familiar with the "willTransition" method of view controllers that lets you detect when a transition to a new UITraitCollection is about to begin.What I need is a callback that happens after the transition is finished. There doesn't seem to be any "didTransition" method, nor any delegate property on the UIViewControllerTransitionCoordinator that I can use for this.How does one obtain this callback?Thanks,Frank

I've seen examples of Swift code with #if DEBUG / #endif, and have even used it myself.I know exactly how preprocessor macros work in c, c++ and Objective-C. In those languages, I know I can say:#ifdef DEBUG ... some code ...#endifAnd I know that if the DEBUG flag is false at build time, the code will not only not run, but it won't even be compiled. This is important to me because the code inside that block contains some sensitive information that must not end up in my compiled code for non-debug builds.In Swift, I'm really not sure what happens. I know the code doesn't execute, but I'm also told that Swift doesn't have a preprocessor. So, what exactly is going on here?Specifically, can I hide sensitive information inside an #if DEBUG block in Swift and be assured that it won't get compiled or in any way be present in the executable when the DEBUG flag is false? Or is #if DEBUG evaluated at runtime in Swift?Thanks,Frank

Hi,I have a universal app that uses the camera along with a preview layer (AVCaptureVideoPreviewLayer) to display a preview of the live camera view.It works fine on an iPhone and fine on an iPad as long as my app is full screen.However, if I open another app in split-view mode, my app loses its live camera view and freezes on the last frame captured.I've tried stopping the AVCaptureSession before the transition and restarting it afterward, and even tearing the whole thing down and building a new one, but neither works.My app is checking permissions and the permissions are fine, and all of the objects created seem valid.Is there some rule that disallows apps from accessing the camera in split screen mode?Frank

Hi,I have an app that includes a very simple one-button interface for recording a video. Our customer wants to be able to switch between the front and rear cameras while the video is being recorded, and without any interruption in the video stream. I notice that even the iOS built-in camera app doesn't do this, but I've heard that some third-party apps do.Is this possible in a practical way? If so, how would I go about it?Thanks,Frank

Hi,How do I check to see if a Character is in a Character Set?In Objective-C, I could write:[[NSCharacterSet lowercaseLetterCharacterSet] characterIsMember:c]Where "c" is a variable of type char.In Swift, I tried to write:CharacterSet.lowercaseLetters.contains(c)Where "c" is of type Character, but I received an error saying that the function was expecting a parameter of type "Unicode.Scalar".Thanks,Frank

Will Apple continue to support it, or will we wake up one day to find that Swift is the only viable language?It's a serious question. Careers depend on it. I don't accept the "No comment" approach that Apple usually takes. It's cruel.I'm willing to put the time into learning Swift if I have to. I'm not going to do it if I don't. I want to know.Frank

I've always understood it to be the case that apps could permit users to log in or use a code to access paid content, as long as the app did not direct the user to an external web site to make a purchase. For example, apps like Netflix or Kindle.My app isn't even doing anything close to this. I have an app in which digital content is unlocked via in-app purchase. Occasionally I give away promo codes that allow a user to unlock one free piece of content. These codes can only be used once, and are distributed in very limited numbers on cards, in person, at events like trade shows.My app has been in the store for about four years using this method. This week I attempted to publish a small bug-fix update, and was flagged by Apple and told that my use of Promo Codes in this manner violates the rules.What happened here? Did Apple misunderstand what my app is doing? Did the rules change recently and I was unaware of the change? Has this always been against the rules, but either Apple didn't enforce it before or they never reviewed my app thorougly enough to find it?Thanks,Frank

I've been using Xcode and Objective-C for years, and rely heavily on the built-in documentation, which is for the most part good.There's an issue that's always bothered me. Today I was looking up a function called class_getName. I found its documentation page, and was also able to navigate to the page showing the overview of the runtime system, all of which is fine.When I typed "class_getName" into my program, the compiler immediately flagged it as an unknown symbol.I knew I probably had to include a header, but none of the documentation pages I looked at mentioned the name of the header file. I had to end up searching the internet for examples until I hit one that showed <objc/runtime.h> being imported.Why isn't this very small, simple and extremely useful bit of information included in the documentation?Frank