How to make SFSpeechRecongnizer Reusable for every UIViewControllers

Question

Currently i'm working on speech to text for iOS 10 feature app. Here blow the code successfully return speech to text on my app. I need to implement this on several time (several viewController) My Question is Can someone explain how to do this as reusable for my every viewControllers. is there any design pattern possible to do. Thanks in advance.

import UIKit

import Speech

class ViewController: UIViewController, SFSpeechRecognizerDelegate {

    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var microphoneButton: UIButton!

    private let speechRecognizer = SFSpeechRecognizer(locale: Locale.init(identifier: "en-US"))!

    private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?
    private var recognitionTask: SFSpeechRecognitionTask?
    private let audioEngine = AVAudioEngine()

    override func viewDidLoad() {
        super.viewDidLoad()

        microphoneButton.isEnabled = false

        speechRecognizer.delegate = self

        SFSpeechRecognizer.requestAuthorization { (authStatus) in

            var isButtonEnabled = false

            switch authStatus {
            case .authorized:
                isButtonEnabled = true

            case .denied:
                isButtonEnabled = false
                print("User denied access to speech recognition")

            case .restricted:
                isButtonEnabled = false
                print("Speech recognition restricted on this device")

            case .notDetermined:
                isButtonEnabled = false
                print("Speech recognition not yet authorized")
            }

            OperationQueue.main.addOperation() {
                self.microphoneButton.isEnabled = isButtonEnabled
            }
        }
    }

    @IBAction func microphoneTapped(_ sender: AnyObject) {
        if audioEngine.isRunning {
            audioEngine.stop()
            recognitionRequest?.endAudio()
            microphoneButton.isEnabled = false
            microphoneButton.setTitle("Start Recording", for: .normal)
        } else {
            startRecording()
            microphoneButton.setTitle("Stop Recording", for: .normal)
        }
    }

    func startRecording() {

        if recognitionTask != nil {  //1
            recognitionTask?.cancel()
            recognitionTask = nil
        }

        let audioSession = AVAudioSession.sharedInstance()  //2
        do {
            try audioSession.setCategory(AVAudioSessionCategoryRecord)
            try audioSession.setMode(AVAudioSessionModeMeasurement)
            try audioSession.setActive(true, with: .notifyOthersOnDeactivation)
        } catch {
            print("audioSession properties weren't set because of an error.")
        }

        recognitionRequest = SFSpeechAudioBufferRecognitionRequest()  //3

        guard let inputNode = audioEngine.inputNode else {
            fatalError("Audio engine has no input node")
        }  //4

        guard let recognitionRequest = recognitionRequest else {
            fatalError("Unable to create an SFSpeechAudioBufferRecognitionRequest object")
        } //5

        recognitionRequest.shouldReportPartialResults = true  //6

        recognitionTask = speechRecognizer.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in  //7

            var isFinal = false  //8

            if result != nil {

                self.textView.text = result?.bestTranscription.formattedString  //9
                isFinal = (result?.isFinal)!
            }

            if error != nil || isFinal {  //10
                self.audioEngine.stop()
                inputNode.removeTap(onBus: 0)

                self.recognitionRequest = nil
                self.recognitionTask = nil

                self.microphoneButton.isEnabled = true
            }
        })

        let recordingFormat = inputNode.outputFormat(forBus: 0)  //11
        inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, when) in
            self.recognitionRequest?.append(buffer)
        }

        audioEngine.prepare()  //12

        do {
            try audioEngine.start()
        } catch {
            print("audioEngine couldn't start because of an error.")
        }

        textView.text = "Say something, I'm listening!"

    }

    func speechRecognizer(_ speechRecognizer: SFSpeechRecognizer, availabilityDidChange available: Bool) {
        if available {
            microphoneButton.isEnabled = true
        } else {
            microphoneButton.isEnabled = false
        }
    }
}

Answer 1

Arguably, that kind of code doesn't really belong in a view controller.

However, to directly answer the question, it seems to me that there are three basic options, roughly in order of preference:

1. Encapsulate the functionality you need in a new class and include that as a property in each of the view controllers than you need it in. (This would also solve the "doesn't belong in a view controller" complaint.)
2. Add a category to UIViewController. This would make your new methods available to all view controllers. You wouldn't be able to edit viewDidLoad and you'd need a setup method (or similar).
3. Subclass UIViewController with your methods and have all your other view controllers inherit from that. However, this would mean you couldn't use other Apple classes like UITableViewController.

   4. Edit UIViewController with swizzling. (Terrible idea. Don't do this.)