In TicTacToe example there is in the override method "PasscodeViewController.viewDidLoad()" this snippet of code: if let browseResult = browseResult, case let NWEndpoint.service(name: name, type: _, domain: _, interface: _) = browseResult.endpoint { title = "Join \(name)" } What confuses me: The use of the "case" keyword without a switch statement. The "case" keyword does not have a constant to compare with to decide if will branch here. And what of the method call to NWEndpoint.service() being set equal to something? Is this actually defining what the service method will do when the system calls it?

I have seen how to connect a button in a storyboard view to code that does its action by dragging that button into the assistant editor. Now I need to do the opposite. There is a button in the storyboard view that is already connected to code. How can that existing already connected code be quickly looked up for a button?

The need is to take pictures with Swift code settable parameters such as F-Stop, exposure time, and zoom level, in an iPhone 14 Pro. What AVCam methods control these? If there are none, are there other ways to do this? The option to have the torch constantly light on, or off, is also needed. Flash will not be used.

The Storyboard Interface Builder has a Switch object that toggles between On, and Off, states. While in the On state it looks normal. While in the Off state it is grayed out. I have a use for this object for the user to toggle between two options which are other than On, and Off. For my intended use its Off state gray out is undesirable. Is there way to prevent this switch graying out in its Off state?

I used the Interface Builder to place a Switch object in a view. I ctrl dragged it into the Assistant to make its handler a method of the class the view's is in, which is itself a subclass of "UITableViewController". A dialog box appear into which I entered the function name, and select the the option to have the sender as an argument. The result is function of the form: @IBAction func switchStateChange(_ sender: UISwitch) { } Now I need to query this Switch's On/Off state from elsewhere in the program, and if necessary change its state. It is not a good solution to save the sender parameter to a global variable because then it would require the user to change this switch's state before that global variable is set. What is needed is to identify, and lookup, this switch object to access it from anywhere in the application. How is this done?

Here is a code snippet by which I attempted to set a neutral white balance: func prepare(completionHandler: @escaping (Error?) -> Void) { func createCaptureSession() { self.captureSession = AVCaptureSession() } func configureCaptureDevices() throws { let session = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back) let cameras = (session.devices.compactMap { $0 }) if cameras.isEmpty { throw CameraControllerError.noCamerasAvailable } for camera in cameras { try camera.lockForConfiguration() camera.setWhiteBalanceModeLocked( with whiteBalanceGains: AVCaptureDevice.WhiteBalanceGains( redGain: 1.0, greenGain: 1.0, blueGain: 1.0), completionHandler handler: ((CMTime) -> Void)? = nil ) // Errors: Extra arguments at positions #2, #3 in call, Cannot find 'with' in scope camera.whiteBalanceMode = .locked camera.unlockForConfiguration() }catch{ // To Do: Error handling here } } My call to "AVCaptureDevice.WhiteBalanceGains()" gets errors. What is the correct way to do this?

The goal is to have the background, and foreground, colors show the current state of a UIButton on a storyboard file. The attempt to do that is done with this code: var toggleLight: Bool = false @IBAction func toggleLight(_ sender: UIButton) { if( toggleLight ){ toggleLight = false sender.baseBackgroundColor = UIColor.black sender.baseForegroundColor = UIColor.white }else{ toggleLight = true sender.baseBackgroundColor = UIColor.white sender.baseForegroundColor = UIColor.black } tableView.reloadData() } I get these errors: Value of type 'UIButton' has no member 'baseBackgroundColor' Value of type 'UIButton' has no member 'baseForegroundColor' I do not understand this because in file "UIKit.UIButton" I see: extension UIButton { ... public var baseForegroundColor: UIColor? public var baseBackgroundColor: UIColor? ... } What has gone wrong there?

I am not able drag a reference object from a Storyboard screen to code in the Assistant. The expected blue line appears as the screenshot shows, but no code is created in the Assistant. This reference object is not in the Launch Screen. When the the screen this object is in is highlighted, the correct file opens in the Assistant. Dragging this object from the "Content View" folder also does not work, even though the blue line also appears. I was recently able to do this. Something changed. What might have changed?

I am attempting to follow this example of how to create a camera app: https://www.appcoda.com/avfoundation-swift-guide/ It describes a sequence of 4 steps, and these steps are embodied in four functions: func prepare(completionHandler: @escaping (Error?) -> Void) { func createCaptureSession() { } func configureCaptureDevices() throws { } func configureDeviceInputs() throws { } func configurePhotoOutput() throws { } DispatchQueue(label: "prepare").async { do { createCaptureSession() try configureCaptureDevices() try configureDeviceInputs() try configurePhotoOutput() } catch { DispatchQueue.main.async { completionHandler(error) } return } DispatchQueue.main.async { completionHandler(nil) } } } What is confusing me is that it appears these four steps need to be executed sequentially, but in the Dispatch Queue they are executed simultaneously because .async is used. For example farther down that webpage the functions createCaptureSession(), and configureCaptureDevices(), and the others, are defined. In createCaptureSession() the member variables self.frontCamera, and self.rearCamera, are given values which are used in configureCaptureDevices(). So configureCaptureDevices() depends on createCaptureSession() having been already executed, something that it appears cannot be depended upon if both functions are executing simultaneously in separate threads. What then is the benefit of using DispatchQueue()? How is it assured the above example dependencies are met? What is the label parameter of the DispatchQueue()'s initializer used for?

I have a warning message that the method AVCapturePhotoOutput.dngPhotoDataRepresentation is deprecated. What has this method been superseded by?

I do not know what I did to make it so, but somehow I accidentally got Xcode Interface Builder to display a storyboard file in an undesired mode which displays the UI buttons, and text fields, in rectangles as shown in the screenshot below. How do I reverse what I did to get it out of this mode?

I have a UITextField object on a storyboard's scene. Its "Editing Did End" event is connected to the view controller's "actIPhoneName()" event handler method as shown in this screenshot. I configured the keyboard to show its "Done" key. I expected that when this Done button is touched, that the keyboard would disappear, and the actIPhoneName() method would be called. But neither of these happen, nor does anything else. The UITextField object remains in edit mode. The breakpoint is never reached. What must I do to make the Done keyboard key work to make the UITextField object lose its First Responder status, and call its "Editing Did End" event handler method?

I have a UITextField object in a storyboard's scene where the user is make numeric entries. Because this field is for numbers only I set the keyboard type to "Number Pad" in attributes. But this keyboard does not have a return key which leaves the user unable to signal when the entry is complete, the keyboard should be put away, and the entered value processed. I tried all the other numeric keyboards also, and found that none of them has a return key. The default keyboard does, but it is a full alphanumeric keyboard which is undesirable for that field. How can I cause the return key, done key, or whichever does that function, appear on a numeric only keyboard?

I added a scene to an existing story board that already has other scenes. I put focus on the new scene, and in the Identity Inspector's "Class" field I gave it a class name. The "Storyboard ID" field did not show in this inspector. Why would it not? No file named after the class name I gave it appeared in the "Project navigator". Is this supposed to happen automatically? Or must I create this Swift file that contains the class definition for the scene manually?

This handler in my photo app: cameraController.captureImage(){ ( image: UIImage?, error: Error? ) in // This closure is the completion handler, it is called when the picture taking is completed. if let error = error { print( "camera completion handler called with error: " + error.localizedDescription ) }else{ print( "camera completion handler called." ) } // If no image was captured return here: guard let image = image else { print(error ?? "Image capture error") return } var phpPhotoLib = PHPhotoLibrary.shared() if( phpPhotoLib.unavailabilityReason.debugDescription != "nil" ){ print( "phpPhotoLib.unavailabilityReason.debugDescription = " + phpPhotoLib.unavailabilityReason.debugDescription ) }else{ // There will be a crash right here unless the key "Privacy - Photo Library Usage Description" exists in this app's .plist file try? phpPhotoLib.performChangesAndWait{ PHAssetChangeRequest.creationRequestForAsset(from: image) } } } asks the user for permission to store the captured photo data in the library. It does this once. It does not ask on subsequent photo captures. Is there a way for app to bypass this user permission request dialog, or at least present it to the user in advance of triggering a photo capture when the app first runs? In this situation the camera is being used to capture science data in a laboratory setting. The scientist using this app already expects, and needs, the photo to be stored. The redundant permission request dialog makes the data collection cumbersome, and inconvenient, due to the extra effort required to reach the camera where it is located.