Swift3 我有一个错误：“；致命错误：在展开可选值“时意外发现nil”；在Xcode 8 swift 3中

这是我的密码

//
//  ViewController.swift
//  morpher app soundboard
//
//  Created by Jared Evan Miller on 7/24/17.
//  Copyright © 2017 Jared Evan Miller. All rights reserved.
//

import UIKit
import AVFoundation

class ViewController: UIViewController {


let soundFilenames = ["5","8","7","4","6","Sound3forbutton3","sound2forbutton1","sound2forbutton2"]
var audioPlayers = [AVAudioPlayer]()
var lastAudioPlayer = 0

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    // Set up audio players
    for sound in soundFilenames {

        do {

            // Try to do something

            let url = URL(fileURLWithPath: Bundle.main.path(forResource: sound, ofType: "wav")!)
            let audioPlayer = try AVAudioPlayer (contentsOf:url)

            audioPlayers.append(audioPlayer)
        }
        catch {

            // Catch the error that is thrown
       audioPlayers.append(AVAudioPlayer())
        }
               }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func buttonTapped(_ sender: UIButton) {

    // Get the audioPlayer that corresponds to the button that they tapped
    let lastPlayer = audioPlayers[lastAudioPlayer]
    lastPlayer.stop();
    lastAudioPlayer = sender.tag;
    lastPlayer.currentTime = 0;
    let audioPlayer = audioPlayers[sender.tag]
    audioPlayer.currentTime=0;
    audioPlayer.play()
}

    @IBAction func tbuttonTapped(_ sender: UIButton) {

    // Get the audioPlayer that corresponds to the button that they tapped

    let lastPlayer = audioPlayers[lastAudioPlayer]
    lastPlayer.stop();
    lastAudioPlayer = sender.tag;
    lastPlayer.currentTime = 0;
    let audioPlayer = audioPlayers[sender.tag]
    audioPlayer.currentTime=0;
    audioPlayer.play()
}

}

我该如何解决这个问题

还有，我得到了这个错误。这是代码中的一部分。看看我改变了什么。当我在iPhone se上运行它时，它会出现错误

!！[我的密码][2]

---

请帮忙

您正在强制展开Budle.main.path…的结果，因为此操作失败，这意味着您的资源未正确加载

确保您的声音文件与应用程序捆绑在一起。您可以通过转到项目设置来检查这一点，然后在“构建阶段”下，将文件添加到“复制捆绑资源”部分（如果它们还不存在）

for sound in soundFilenames {

    guard let urlString = Bundle.main.path(forResource: sound, ofType: "wav") else {

        print("Sound file not found: \(sound)")

        continue
    }

    let url = URL(fileURLWithPath:urlString)

    do {

        // Try to do something
        let audioPlayer = try AVAudioPlayer (contentsOf:url)

        audioPlayers.append(audioPlayer)
    }
    catch {

        // Catch the error that is thrown
        audioPlayers.append(AVAudioPlayer())
    }
}