Question

我在使用系统声音按下按钮时尝试播放声音。我一直收到错误：＆＃34;致命错误：在打开一个可选值＆＃34;时意外地发现了nil。我试过调试，我相信错误发生在 var ref 行。＆＃34; roar.aif＆＃34;是我在项目中包含的自定义声音。它只有一个半长。我会很感激的建议。谢谢！

        var soundID: SystemSoundID = SystemSoundID()
        var mainBundle: CFBundleRef = CFBundleGetMainBundle()
        var ref: CFURLRef = CFBundleCopyResourceURL(mainBundle, "roar.aif", nil, nil) as CFURLRef!
        println("Here is your ref: \(ref)")
        AudioServicesCreateSystemSoundID(ref, &soundID)
        AudioServicesPlaySystemSound(soundID)

Answer 1

我认为正确的方法是在第三个参数中使用filetype：

    var soundID: SystemSoundID = 0
    var mainBundle: CFBundleRef = CFBundleGetMainBundle()
    if let ref: CFURLRef = CFBundleCopyResourceURL(mainBundle, CFSTR("roar"), CFSTR("aif"), nil) {
        println("Here is your ref: \(ref)")
        AudioServicesCreateSystemSoundID(ref, &soundID)
        AudioServicesPlaySystemSound(soundID)
    } else {
        println("Could not find sound file")
    }

你确定文件是roar.aif而不是roar.aiff吗？

确保该文件不在子目录中，如果是这样，您必须将其添加为第四个参数。

请参阅：https://developer.apple.com/library/mac/documentation/CoreFoundation/Reference/CFBundleRef/index.html#//apple_ref/c/func/CFBundleCopyResourceURL

Answer 2

为了扩展Tom的答案（这是完全正确的），这里有一个稍微强大的错误处理程序（这将有助于平息Apple的应用程序测试人员）

else {
        let networkIssueController = UIAlertController(title: "Error", message: "Unable to find an audio file!", preferredStyle: .Alert)
        let okButton = UIAlertAction(title: "OK", style: .Default, handler: nil)
        networkIssueController.addAction(okButton)

        let cancelButton = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
        networkIssueController.addAction(cancelButton)

        self.presentViewController(networkIssueController, animated: true, completion: nil)// you have to display the alert after you create it

}

Answer 3

Swift 2.0

func createSystemSoundID() -> SystemSoundID {
    var soundID: SystemSoundID = 0
    let soundURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), "roar", "aiff", nil)
    AudioServicesCreateSystemSoundID(soundURL, &soundID)
    return soundID
}

创建一次：

let systemSoundID = createSystemSoundID()

随意调用：

AudioServicesPlaySystemSound(systemSoundID)

Answer 4

Swift 4.1

if let path = Bundle.main.path(forResource: "roar", ofType: "aif") {
    let url = URL(fileURLWithPath: path) as CFURL
    var soundID: SystemSoundID = 0
    AudioServicesCreateSystemSoundID(url, &soundID)
    AudioServicesPlaySystemSound(soundID)
} else {
    print("file not found!")
}

使用Swift播放系统声音

4 个答案: