最近才发现，其实系统已经提供了语音转成文字的API，于是立马去试了一下。结果发现很不错，速度也还可以。支持iOS10级以上的版本，需要麦克风权限和语音识别权限。下面来看看如何达到效果（没有深入的理解，但是可以用了）。
一、引入系统库
import Speech
二、主要的类
-
SFSpeechRecognizer声音处理器
langugeSimple 要语音识别的语言简称，具体有哪些可以看上一篇语音阅读
SFSpeechRecognizer(locale: Locale(identifier: langugeSimple))
这句会根据传入的语言简称来返回一个声音处理器，如果不支持，怎会返回nil。更多细节可以查看官方文档。
通过下面的方法来得到语音识别的结果
// Recognize speech utterance with a request
// If request.shouldReportPartialResults is true, result handler will be called
// repeatedly with partial results, then finally with a final result or an error.
open func recognitionTask(with request: SFSpeechRecognitionRequest, resultHandler: @escaping (SFSpeechRecognitionResult?, Error?) -> Void) -> SFSpeechRecognitionTask
-
AVAudioEngine专门用来处理声音的数据
这里细节不在介绍了，直接上使用的代码
lazy var audioEngine: AVAudioEngine = {
let audioEngine = AVAudioEngine()
audioEngine.inputNode.installTap(onBus: 0, bufferSize: 1024, format: audioEngine.inputNode.outputFormat(forBus: 0)) { (buffer, audioTime) in
// 为语音识别请求对象添加一个AudioPCMBuffer，来获取声音数据
self.recognitionRequest.append(buffer)
}
return audioEngine
}()
-
SFSpeechAudioBufferRecognitionRequest语音识别器
// 语音识别器
lazy var recognitionRequest: SFSpeechAudioBufferRecognitionRequest = {
let recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
return recognitionRequest
}()
-
SFSpeechRecognitionTask语言识别任务管理器，启用和关闭都要使用这个管理进行
public enum SFSpeechRecognitionTaskState : Int {
case starting // Speech processing (potentially including recording) has not yet begun
case running // Speech processing (potentially including recording) is running
case finishing // No more audio is being recorded, but more recognition results may arrive
case canceling // No more recognition reuslts will arrive, but recording may not have stopped yet
case completed // No more results will arrive, and recording is stopped.
}
二、完整的代码
import UIKit
import Speech
enum LGSpeechType: Int {
case start
case stop
case finished
case authDenied
}
typealias LGSpeechBlock = (_ speechType: LGSpeechType, _ finalText: String?) -> Void
@available(iOS 10.0, *)
class LGSpeechManager: NSObject {
private var parentVc: UIViewController!
private var speechTask: SFSpeechRecognitionTask?
// 声音处理器
private var speechRecognizer: SFSpeechRecognizer?
static let share = LGSpeechManager()
private var block: LGSpeechBlock?
// 语音识别器
lazy var recognitionRequest: SFSpeechAudioBufferRecognitionRequest = {
let recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
return recognitionRequest
}()
lazy var audioEngine: AVAudioEngine = {
let audioEngine = AVAudioEngine()
audioEngine.inputNode.installTap(onBus: 0, bufferSize: 1024, format: audioEngine.inputNode.outputFormat(forBus: 0)) { (buffer, audioTime) in
// 为语音识别请求对象添加一个AudioPCMBuffer，来获取声音数据
self.recognitionRequest.append(buffer)
}
return audioEngine
}()
func lg_startSpeech(speechVc: UIViewController, langugeSimple: String, speechBlock: @escaping LGSpeechBlock) {
parentVc = speechVc
block = speechBlock
lg_checkmicroPhoneAuthorization { (microStatus) in
if microStatus {
self.lg_checkRecognizerAuthorization(recongStatus: { (recStatus) in
if recStatus {
// 初始化语音处理器的输入模式 语音处理器准备就绪（会为一些audioEngine启动时所必须的资源开辟内存）
self.audioEngine.prepare()
if (self.speechTask?.state == .running) { // 如果当前进程状态是进行中
// 停止语音识别
self.lg_stopDictating()
} else { // 进程状态不在进行中
self.speechRecognizer = SFSpeechRecognizer(locale: Locale(identifier: langugeSimple))
guard (self.speechRecognizer != nil) else {
self.showAlert("抱歉，暂不支持当前地区使用语音输入")
return
}
self.lg_setCallBack(type: .start, text: nil)
// 开启语音识别
self.lg_startDictating()
}
} else {
self.showAlert("您已取消授权使用语音识别，如果需要使用语音识别功能，可以到设置中重新开启！")
self.lg_setCallBack(type: .authDenied, text: nil)
}
})
} else {
//麦克风没有授权
self.showAlert("您已取消授权使用麦克风，如果需要使用语音识别功能，可以到设置中重新开启！")
self.lg_setCallBack(type: .authDenied, text: nil)
}
}
}
}
@available(iOS 10.0, *)
extension LGSpeechManager: SFSpeechRecognitionTaskDelegate {
//判断语音识别权限
private func lg_checkRecognizerAuthorization(recongStatus: @escaping (_ resType: Bool) -> Void) {
let authorStatus = SFSpeechRecognizer.authorizationStatus()
if authorStatus == .authorized {
recongStatus(true)
} else if authorStatus == .notDetermined {
SFSpeechRecognizer.requestAuthorization { (status) in
if status == .authorized {
recongStatus(true)
} else {
recongStatus(false )
}
}
} else {
recongStatus(false)
}
}
//检测麦克风
private func lg_checkmicroPhoneAuthorization(authoStatus: @escaping (_ resultStatus: Bool) -> Void) {
let microPhoneStatus = AVCaptureDevice.authorizationStatus(for: .audio)
if microPhoneStatus == .authorized {
authoStatus(true)
} else if microPhoneStatus == .notDetermined {
AVCaptureDevice.requestAccess(for: .audio, completionHandler: {(res) in
if res {
authoStatus(true)
} else {
authoStatus(false)
}
})
} else {
authoStatus(false)
}
}
//开始进行
private func lg_startDictating() {
do {
try audioEngine.start()
speechTask = speechRecognizer!.recognitionTask(with: recognitionRequest) { (speechResult, error) in
// 识别结果，识别后的操作
if speechResult == nil {
return
}
self.lg_setCallBack(type: .finished, text: speechResult!.bestTranscription.formattedString)
}
} catch {
print(error)
self.lg_setCallBack(type: .finished, text: nil)
}
}
// 停止声音处理器，停止语音识别请求进程
func lg_stopDictating() {
lg_setCallBack(type: .stop, text: nil)
audioEngine.stop()
recognitionRequest.endAudio()
speechTask?.cancel()
}
private func lg_setCallBack(type: LGSpeechType, text: String?) {
if block != nil {
block!(type, text)
}
}
private func showAlert(_ message: String) {
let alertVC = UIAlertController(title: nil, message: message, preferredStyle: .alert)
let firstAction = UIAlertAction(title: "知道了", style: .default, handler: {(action) in
})
alertVC.addAction(firstAction)
parentVc.present(alertVC, animated: true, completion: nil)
}
}
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