从Bundle复制文件时Swift FileManager错误

我评论了下面代码中导致问题的那一行.

这是一切：

// This function returns the path to the Documents folder:
func pathToDocsFolder() -> String {
    let pathToDocumentsFolder = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)[0] as String

    return pathToDocumentsFolder.stringByAppendingPathComponent("/moviesDataBase.sqlite")
}


override func viewDidLoad() {
    super.viewDidLoad()

    let theFileManager = NSFileManager.defaultManager()

    if theFileManager.fileExistsAtPath(pathToDocsFolder()) {
        println("File Found!")
        // And then open the DB File
    }
    else {
        // Copy the file from the Bundle and write it to the Device:
        let pathToBundledDB = NSBundle.mainBundle().pathForResource("moviesDB",ofType: "sqlite")
        let pathToDevice = pathToDocsFolder()

        let error:NSError?

        // Here is where I get the error:
        if (theFileManager.copyItemAtPath(pathToBundledDB,toPath:pathToDevice,error:error)) {
            // success
        }
        else {
            // failure 
        }
    }
}

该应用程序甚至不会立即编译.这个问题似乎特别针对copyItemAtPath调用 – 它应该返回一个Bool.

我很欣赏任何见解.