Xcode 8.1 Swift 3 错误：无法将“String”类型的值转换为预期的参数类型“UnsafeMutableRawPointer”

Question

包含 var sceneData 代码的行给出了错误，显然是因为“路径”字符串。有谁知道如何解决这个问题？谢谢！

extension SKNode {
    class func unarchiveFromFile(_ file : String) -> SKNode? {
        if let path = Bundle.main.path(forResource: file, ofType: "sks") {
            var sceneData = Data(bytesNoCopy: path, count: .DataReadingMappedIfSafe, deallocator: nil)!
            var archiver = NSKeyedUnarchiver(forReadingWithData: sceneData)

            archiver.setClass(self.classForKeyedUnarchiver(), forClassName: "SKScene")
            let scene = archiver.decodeObjectForKey(NSKeyedArchiveRootObjectKey) as! GameScene
            archiver.finishDecoding()
            return scene
        } else {
            return nil
        }
    }
}

Answer 1

Data(bytesNoCopy: 需要一个指针而不是字符串路径。

从磁盘读取Data 的API 是Data(contentsOf，但是它需要一个URL

extension SKNode {
  class func unarchiveFromFile(_ file : String) -> SKNode? {
    if let url = Bundle.main.url(forResource: file, withExtension: "sks") {
      do {
        var sceneData = try Data(contentsOf: url)
        var archiver = NSKeyedUnarchiver(forReadingWith: sceneData)

        archiver.setClass(self.classForKeyedUnarchiver(), forClassName: "SKScene")
        let scene = archiver.decodeObjectForKey(NSKeyedArchiveRootObjectKey) as! GameScene
        archiver.finishDecoding()
        return scene
      } catch {
        return nil
      }
    } else {
      return nil
    }
  }
}

在 Swift 3 中，我将方法重命名为

class func unarchive(from file : String) -> SKNode? { ...