I've got a simple app delegate method to create a core data object when my push notification arrives. The save() is returning nilError and I can't figure out what I'm doing wrong. I've verified all the elements of Message have expected data. The attributes are just String, Data, and Date types. class AppDelegate: NSObject, UIApplicationDelegate {  @Environment(\.managedObjectContext) private var managedObjectContext   func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {   guard let text = userInfo["text"] as? String,      let image = userInfo["image"] as? String,      let url = URL(string: image) else {    completionHandler(.noData)    return   }   let context = self.managedObjectContext   URLSession.shared.dataTask(with: url) { data, response, error in    guard let data = data, error == nil else {     completionHandler(.failed)     return    }    context.perform {     let message = Message(context: context)     message.text = text     message.image = data     message.received = Date()     do {      try context.save()      completionHandler(.newData)     } catch {      print(error)      completionHandler(.failed)     }    }   }.resume()  }

How do I get errors from the simulator when something is wrong with the pkpass file? I have a 'good' version of my pass.json that drags into the simulator without issues. I have a different version that does nothing, so clearly something is wrong with the JSON, but I can't find what.In the simulator I've done Debug -> Open System Log but when I drag in the bad pkpass file, nothing is displayed.

I'm trying to wrap my head around Combine still, and so in my class that handles web requests I've written this method:static func downloadNumbersPublisher(datesByType: [LottoType: (start: Date, end: Date)]) -> URLSession.DataTaskPublisher { guard let url = downloadUrl(using: datesByType) else { return } var request = URLRequest(url: url) request.addValue("gzip", forHTTPHeaderField: "Accept-Encoding") let session = URLSession(configuration: .ephemeral) return session.dataTaskPublisher(for: request) }What I'm not clear on though is what I actually return on line 2, the guard statement.

In Apple's documentation it says this:"This method, though convenient, is inefficient if used multiple times in succession. Achieve better performance by chaining filters without asking for the outputs of individual filters."That confuses me though because I don't know how to link them together without getting the output. For example, this is my method to apply a TiltShift filter, based on the instructions from Apple's docs. When I perform the gradient filter, I have to take the outputImage of that to pass into the next filter. What's the right way to be doing this? override public var outputImage: CIImage? { guard let inputImage = inputImage else { return nil } let clamped = inputImage.clampedToExtent() let blurredImage = clamped.applyingGaussianBlur(sigma: inputRadius) var gradientParameters = [ "inputPoint0": CIVector(x: 0, y: 0.75 * inputImage.extent.height), "inputColor0": CIColor(red: 0, green: 1, blue: 0, alpha: 1), "inputPoint1": CIVector(x: 0, y: 0.5 * inputImage.extent.height), "inputColor1": CIColor(red: 0, green: 1, blue: 0, alpha: 0) ]; guard let gradientImage = ciImage(from: "CILinearGradient", parameters: gradientParameters) else { return nil } gradientParameters["inputPoint0"] = CIVector(x: 0, y: 0.25 * inputImage.extent.height) guard let backgroundGradientImage = ciImage(from: "CILinearGradient", parameters: gradientParameters) else { return nil } let maskParameters = [ kCIInputImageKey: gradientImage, kCIInputBackgroundImageKey: backgroundGradientImage ] guard let maskImage = ciImage(from: "CIAdditionCompositing", parameters: maskParameters) else { return nil } let combinedParameters = [ kCIInputImageKey: blurredImage, kCIInputBackgroundImageKey: clamped, kCIInputMaskImageKey: maskImage ] return ciImage(from: "CIBlendWithMask", parameters: combinedParameters) } private func ciImage(from filterName: String, parameters: [String: Any]) -> CIImage? { guard let filtered = CIFilter(name: filterName, parameters: parameters) else { return nil } return filtered.outputImage }

Apple's docs show using NSString.localizedUserNotificationString for local push notifications in Swift. Why not just use the normal NSLocalizedString() methods? Is there something special about the former method?

When I try to re-open the storyboard I was just editing in the current production version of Xcode it says"The document Main.storyboard could not be opened. The operation couldn't be completed. (com.apple.InterfaceBuilder error -1)"What in the world do I do to fix that? I *really* don't want to go back to my last git commit for that file because there have been quite extensive changes with pretty complex autolayout settings.

I'm trying to write a method to take a string and break it up into an array where each element of the array is the next 10 characters. So a string that's 32 characters long would end up with 3 array elements containing the first 30 characters, and then the 4th array element would have the last 2 characters. I was trying to use substringWithRange for this but as soon as I advance past the str.endIndex it throws an exception, and I can't figure out how to work around that. I know it's just a silly syntax thing, but I'm stuck.

On a view controller shown as part of a UINavigationController's stack, how do I tell if the Back button was pressed? The previously suggested answer from ages ago, to check isBeingDismissed(), seems to always return a false value.