当耳机插入时强制通过耳机插孔进行iOS录音

Question

我有一个错误，在音频捕获期间插入一组耳机，音频捕获仍然通过板载麦克风发生，并通过扬声器播放。我正在尝试通过音频端口捕获此音频，如果耳机已插入并正在使用中。这是我的代码的副本：

    @IBAction func recordAudio(_ sender: UIButton) {
    isPlayingRecording = false;
    if endTime == nil {
        self.startTimer()
    }
    recordingInProgress.text = "Recording"
    recordingInProgress.isHidden = false
    stopButton.isHidden = false
    recordButton.isEnabled = false

    setSecondaryView()

    let dirPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
    let recordingName = "\(exercise!.exerciseId).m4a"

    let pathArray = [dirPath, recordingName]
    filePath = NSURL.fileURL(withPathComponents: pathArray) as NSURL?

    //Set up audio session
    let session = AVAudioSession.sharedInstance()
    do {
        try session.setCategory(AVAudioSessionCategoryPlayAndRecord)
    } catch _ {
    }

    do {
        // setup how audio is going to be used (ie. audio parameters, categories, speaker)
        try session.overrideOutputAudioPort(AVAudioSessionPortOverride.speaker)
    } catch _ {
    }

    //Initialize and prepare the recorder
    audioRecorder = nil
    do {
        let recordSettings: [String : AnyObject] = [AVFormatIDKey:Int(kAudioFormatMPEG4AAC) as AnyObject,
            AVSampleRateKey:44100.0 as AnyObject,
            AVNumberOfChannelsKey:1 as AnyObject,
            AVEncoderAudioQualityKey:AVAudioQuality.medium.rawValue as AnyObject
        ]
        try audioRecorder = AVAudioRecorder(url: filePath! as URL, settings:recordSettings)
    } catch _ {
    }

    if audioRecorder != nil {
        audioRecorder.delegate = self   //This statement makes "RecordViewController" a delegate of "AVAudioRecorder", so that we can use "audioRecorderDidFinishRecording" function later on
        audioRecorder.isMeteringEnabled = true
        audioRecorder.prepareToRecord()
        audioRecorder.record()
    }

    //Start count up timer if the exercise doesn't have a attempt time constraint.
    if(exercise != nil && exercise?.skill != nil && exercise!.skill.respondtime == nil && exercise!.skill.respondtime!.intValue > 0) {
        startTime = Date().timeIntervalSince1970
        timerLabel.isHidden = false
        timerLabel.text = readableSecondString(0.0) as String
        timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(RecordSoundsViewController.tick), userInfo: nil, repeats: true)
    }
}

当插入一组耳机时，如何通过音频端口/耳机插孔捕获音频？我是用Swift做的。