Swift &引用；Thread1:致命错误：在展开可选值“0”时意外发现零；

这些是我使用的wav文件

我附上了一个屏幕截图，它是抛出这个错误

这就是我现在拥有的。我以为我一切都对。我知道这与使用可选的方法有关，但不确定如何修复它

import UIKit
import AVFoundation

class SecondViewController: UIViewController
{
    var audioPlayer: AVAudioPlayer?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        do
        {
            let catSound = Bundle.main.path(forResource: "Cat", ofType: "wav")
            let horseSound = Bundle.main.path(forResource: "Horse", ofType: "wav")
            let dogSound = Bundle.main.path(forResource: "Dog", ofType: "wav")
            let raccoonSound = Bundle.main.path(forResource: "Raccoon", ofType: "wav")

            audioPlayer = try AVAudioPlayer(contentsOf: URL(fileURLWithPath: catSound!))
            audioPlayer = try AVAudioPlayer(contentsOf: URL(fileURLWithPath: horseSound!))
            audioPlayer = try AVAudioPlayer(contentsOf: URL(fileURLWithPath: dogSound!))
            audioPlayer = try AVAudioPlayer(contentsOf: URL(fileURLWithPath: raccoonSound!))
        }
        catch
        {
            print(error)///
        }
    }

    @IBAction func cat(_ sender: Any)
    {
        audioPlayer?.play()
    }
    @IBAction func horse(_ sender: Any)
    {
        audioPlayer?.play()
    }
    @IBAction func dog(_ sender: Any)
    {
        audioPlayer?.play()
    }
    @IBAction func raccoon(_ sender: Any){
        audioPlayer?.play()
    }
}

---

你的一个资源是零。 在（强制）展开之前，应检查您的分辨率是否为零：

if let catSound = Bundle.main.path(forResource: "Cat", ofType: "wav")
{
    audioPlayer = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: catSound))
}

---

对每个资源执行此操作，并使用调试器查看哪一个是nil。

正如@Chris和@inexcitus所提到的，您的完整代码如下所示

class SecondViewController: UIViewController {

    var audioPlayer: AVAudioPlayer?
    override func viewDidLoad() {
      super.viewDidLoad()
    }

    @IBAction func cat(_ sender: Any)
    {
       if  let catSound = Bundle.main.path(forResource: "cat", ofType: "wav") {
           audioPlayer = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: catSound))
           audioPlayer?.play()
       }else {
        print("Cat File is missing")
       }

    }
    @IBAction func horse(_ sender: Any)
    {
       if  let horseSound = Bundle.main.path(forResource: "horse", ofType: "wav") {
          audioPlayer = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: horseSound))
          audioPlayer?.play()
       }else {
        print("Horse File is missing")
       }
    }


    @IBAction func dog(_ sender: Any)
    {
       if  let dogSound = Bundle.main.path(forResource: "dog", ofType: "wav") {
          audioPlayer = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: dogSound))
          audioPlayer?.play()
       }else {
        print("Dog File is missing")
       }
    }
    @IBAction func raccoon(_ sender: Any)
    {
       if  let raccoonSound = Bundle.main.path(forResource: "raccoon", ofType: "wav") {
          audioPlayer = try? AVAudioPlayer(contentsOf: URL(fileURLWithPath: raccoonSound))
          audioPlayer?.play()
       }else {
        print("Raccoon File is missing")
       }
   }}

---

区分大小写很重要。

文件是小写的（“cat”），但代码中的参数字符串是大写的（“cat”）。参数字符串和文件名必须完全匹配

您的代码无论如何都不是很有用，因为它在

viewDidLoad

中覆盖音频播放器实例三次

一个更有效的解决方案是创建一种方法来加载文件和播放声音，并使用

Bundle

的URL相关API

强制展开很好，因为所有文件都必须在编译时在包中。可以立即修复设计错误（文件丢失或名称拼写错误）

class SecondViewController: UIViewController
{
    var audioPlayer: AVAudioPlayer!

    @IBAction func cat(_ sender: Any) {
        playSound(withName: "cat")
    }

    @IBAction func horse(_ sender: Any) {
        playSound(withName: "horse")
    }

    @IBAction func dog(_ sender: Any) {
        playSound(withName: "dog")
    }

    @IBAction func raccoon(_ sender: Any){
        playSound(withName: "raccoon")
    }

    func playSound(withName name : String) {
        let sound = Bundle.main.url(forResource: name, withExtension: "wav")!
        audioPlayer = try! AVAudioPlayer(contentsOf: sound)
        audioPlayer.play()
    }
}

---

当您遇到该错误时，请查找感叹号（

！

），这意味着一个可选项正在强制展开。我认为你的声音是错误的。另外，您为每个声音设置了相同的音频播放器实例，因此只有最后一个声音会保留。尝试在每个按钮动作中设置声音。这是否回答了您的问题？如果可能的话，请您共享崩溃行的屏幕截图。将

URL（fileURLWithPath:catSound！）

替换为可选，而不是强制展开<代码>URL（fileURLWithPath:catSound？？？）。若强制展开的值为零，则强制展开将崩溃。您还可以在Xcode中共享音频文件的屏幕截图吗