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Reply to How can I get my app to wait for a permission request to complete?
So I created the code below, and the weird thing was that the output read: going in... and we're out Need to ask user So essentially it blows right through the semaphore. However, if I declare the semaphore with 0, then the first semaphore.wait() is successful, and the program freezes because the userAlert permission box never pops up. What is going on here? print ("going in...") let semaphore = DispatchSemaphore(value: 1 ) DispatchQueue.global(qos: .userInitiated).async { let mediaAuthorizationStatus = AVCaptureDevice.authorizationStatus(for: .audio) switch mediaAuthorizationStatus { case .denied: print (".denied") case .authorized: print ("authorized") case .restricted: print ("restricted") case .notDetermined: print("Need to ask user") semaphore.wait() AVCaptureDevice.requestAccess(for: .audio, completionHandler: { (granted: Bool) in if granted { semaphore.signal() } else { semaphore.signal() } }) @unknown default: print("unknown") } print ("\(semaphore.debugDescription)") } semaphore.wait() print ("and we're out")
Feb ’22
Reply to My writing the installTap buffer to an AVAudioFile seems to fail data-wise, or at the end
It's kind of kludgy but someone gave me the answer here: https://stackoverflow.com/questions/70616820/my-writing-the-installtap-buffer-to-an-avaudiofile-seems-to-fail-data-wise/70618216?noredirect=1#comment124895854_70618216 You need to let your AVAudioFile go out of scope (nil it at some point), that's how you call AVAudioFile's close() method, which presumably finishes writing out header information.
Jan ’22
Reply to Is .installTap the equivalent of a C callback function?
This is a rewriting of my original question, once I realized I was reading the flow incorrectly. Working on a speech to text demo, which works. But I am still trying to learn the flow of Swift. While I may be calling it incorrectly, I'm looking at the closure in node.installTap as a C callback function. When the buffer is full, the code within the closure is called. From what I interpret here, every time the buffer becomes full, the closure from within the node.installTap runs. What I can't figure out is what triggers the closure within: task = speechRecognizer?.recognitionTask(with: request, resultHandler: {}) The entire demo below works, am just trying to figure out how the AVAudioEngine knows when to call that second closure. Is there some connection? func startSpeechRecognition (){ let node = audioEngine.inputNode let recordingFormat = node.outputFormat(forBus: 0) node.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, _) in self.request.append(buffer) } audioEngine.prepare() do { try audioEngine.start() } catch let error { ... } guard let myRecognition = SFSpeechRecognizer() else { ... return } if !myRecognition.isAvailable { ... } task = speechRecognizer?.recognitionTask(with: request, resultHandler: { (response, error) in guard let response = response else { if error != nil { print ("\(String(describing: error.debugDescription))") } else { print ("problem in repsonse") } return } let message = response.bestTranscription.formattedString print ("\(message)") }) }
Dec ’21
Reply to Why does a dismissed child UIView doesn't reappear properly after its first appearance?
Experimenting around I found that if I didn't set the child's constraints (see below), then it would always work. Is there a method to remove the constraints of a UIView before deleting it? vc is the Child UIView and pc is its parent func setConstraints (vc: UIViewController, pc: UIView) { vc.view.translatesAutoresizingMaskIntoConstraints = false var constraints = [NSLayoutConstraint]() constraints.append(vc.view.leadingAnchor.constraint(equalTo: pc.safeAreaLayoutGuide.leadingAnchor)) constraints.append(vc.view.trailingAnchor.constraint(equalTo: pc.safeAreaLayoutGuide.trailingAnchor)) constraints.append(vc.view.bottomAnchor.constraint(equalTo: pc.safeAreaLayoutGuide.bottomAnchor)) constraints.append(vc.view.topAnchor.constraint(equalTo: pc.safeAreaLayoutGuide.topAnchor)) NSLayoutConstraint.activate(constraints) }
Dec ’21