使用Cocoa Touch如何集成实时语音识别功能

要在iOS应用中集成实时语音识别功能，可以使用苹果的Speech框架。Speech框架提供了简单易用的API，可以实现实时语音识别功能。以下是一个简单的示例代码，演示如何使用Speech框架实现实时语音识别功能：

import UIKit
import Speech

class ViewController: UIViewController, SFSpeechRecognizerDelegate {

    @IBOutlet weak var transcriptionLabel: UILabel!
    private let speechRecognizer = SFSpeechRecognizer(locale: Locale(identifier: "en-US"))
    private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?
    private var recognitionTask: SFSpeechRecognitionTask?
    private let audioEngine = AVAudioEngine()

    override func viewDidLoad() {
        super.viewDidLoad()
        speechRecognizer?.delegate = self
        SFSpeechRecognizer.requestAuthorization { authStatus in
            OperationQueue.main.addOperation {
                if authStatus == .authorized {
                    try! self.startRecording()
                }
            }
        }
    }

    func startRecording() throws {
        if let recognitionTask = recognitionTask {
            recognitionTask.cancel()
            self.recognitionTask = nil
        }

        let audioSession = AVAudioSession.sharedInstance()
        try audioSession.setCategory(.record, mode: .measurement, options: .duckOthers)
        try audioSession.setActive(true, options: .notifyOthersOnDeactivation)

        recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
        let inputNode = audioEngine.inputNode
        guard let recognitionRequest = recognitionRequest else { fatalError("Unable to create recognition request") }

        recognitionRequest.shouldReportPartialResults = true

        recognitionTask = speechRecognizer?.recognitionTask(with: recognitionRequest) { result, error in
            var isFinal = false

            if let result = result {
                self.transcriptionLabel.text = result.bestTranscription.formattedString
                isFinal = result.isFinal
            }

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

                try! self.startRecording()
            }
        }

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

        audioEngine.prepare()
        try audioEngine.start()

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

    func speechRecognizer(_ speechRecognizer: SFSpeechRecognizer, availabilityDidChange available: Bool) {
        if available {
            try! startRecording()
        } else {
            audioEngine.stop()
            recognitionRequest?.endAudio()
        }
    }
}

在上面的示例代码中，我们首先导入Speech框架，并在ViewController类中实现SFSpeechRecognizerDelegate协议。在viewDidLoad方法中，我们请求用户授权访问语音识别功能，并调用startRecording方法开始实时语音识别。

在startRecording方法中，我们首先创建一个SFSpeechAudioBufferRecognitionRequest对象，然后设置音频输入节点和回调函数，实时处理语音识别结果。在回调函数中，我们更新UI界面显示语音识别的结果，并在识别完成或出现错误时重新开始识别。

最后，在speechRecognizer方法中，我们实现了SFSpeechRecognizerDelegate协议的availabilityDidChange方法，用于处理语音识别功能的可用性变化事件。当语音识别功能可用时，我们调用startRecording方法开始实时语音识别。