SWIFT：NSURL 总是 Nil 或不可用

Question

所以在我的 Swift 应用程序中，我有一个选择文件夹/驱动器的函数 - 然后我想使用 NSURL 作为字符串。但是-当我打印 NSURL 时，它显示为“可选（文件：///（这里的东西）”但是当我将其设为字符串时，它显示为 Nil。我做错了什么吗？ 代码如下

@IBAction func selectDrive(sender: AnyObject) {
    var openPanel = NSOpenPanel()
    openPanel.allowsMultipleSelection = false
    openPanel.canChooseDirectories = true
    openPanel.canCreateDirectories = true
    openPanel.canChooseFiles = false
    openPanel.beginWithCompletionHandler { (result) -> Void in
        if result == NSFileHandlingPanelOKButton {
            println(openPanel.URL)
            self.url = openPanel.URL!

            var loc = String(contentsOfURL: self.url)
            println("Location is at \(loc)")
            // var str = String(system("diskutil info \(loc) | grep UUID:"))

        }

    }
}

我还在顶部声明了以下内容

var url = NSURL()
@IBOutlet weak var driveLabel: NSTextField!

任何帮助将不胜感激。昨晚我花了几个小时试图让控制台输出作为字符串返回，尝试将 NSURL 转换为字符串，尝试删除整个应用程序......

Answer 1

NSOpenPanel 总是返回带有 file:// 方案的 url，您可以使用其 path 属性获取字符串表示

@IBAction func selectDrive(sender: AnyObject) {
    var openPanel = NSOpenPanel()
    openPanel.allowsMultipleSelection = false
    openPanel.canChooseDirectories = true
    openPanel.canCreateDirectories = true
    openPanel.canChooseFiles = false
    openPanel.beginWithCompletionHandler { (result) -> Void in
        if result == NSFileHandlingPanelOKButton {

            self.url = openPanel.URL!
            println("Location is at \(self.url.path!)")
        }
    }
}