"" "스레드 1 : 예외 : 0x7fb12cc088c0" "" "예외 오류로 전송 된 인식 할 수없는 선택기

Udacity로 Xcode를 배우고 있습니다. 예외 오류로 인해 문제가 발생했습니다. 여기 내 ViewController.swift 문서가 있습니다.

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var recordingLabel: UILabel!
    @IBOutlet weak var recordButton: UIButton!
    @IBOutlet weak var stopRecordingButton: UIButton!
    
    func buttonAction(sender:UIButton){
        
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        stopRecordingButton.isEnabled = false
        
        // Do any additional setup after loading the view.
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        print("viewWillAppear called")
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // depose of any resources that can be recreated
    }
    
    @IBAction func recordAudio(_ sender: AnyObject){
            recordingLabel.text = "Recording in Progress"
            stopRecordingButton.isEnabled = true
            recordButton.isEnabled = false
    }
    
    @IBAction func stopRecording(_ sender: AnyObject) {
        recordButton.isEnabled = true
        stopRecordingButton.isEnabled = false
        recordingLabel.text = "Tap to record"
    }

}

그리고 여기 내 AppDelegate.swift가 있습니다.

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {



    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        return true
    }

    // MARK: UISceneSession Lifecycle

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }


}

내 오류 메시지는 다음과 같습니다. Thread 1 : Exception : "-[SingingScope_Storyboard.ViewController recordButton :] : unrecognized selector sent to instance 0x7fb12cc088c0"

이것을 디버그하려면 어떻게해야합니까? 감사합니다!