ios - swift3中的编译错误:“AnyObject”不是“NSObject”的子类型

Question

在基于Swift 3的编译过程中，我面临以下错误。

class DetailViewController: UIViewController {

      @IBOutlet weak var detailDescriptionLabel: UILabel!


      var detailItem: AnyObject? {
        didSet {
            // Update the view.
            self.configureView()
        }
      }

      func configureView() {
        // Update the user interface for the detail item.
        if let detail: AnyObject = self.detailItem {
            if let label = self.detailDescriptionLabel {
                label.text = detail.valueForKey("timeStamp")!.description
            }
        }
      }

      override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.configureView()
      }

      override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
      }


    }

错误:

/.../DetailViewController.swift:27:33:'AnyObject'不是以下内容的子类型
'NSObject'

Answer 1

if let detail: [String: AnyObject] = self.detailItem {
        if let label = self.detailDescriptionLabel {
            label.text = detail.valueForKey("timeStamp")!.description
        }
    }

如果detailItem用于存储JSON对象，则最好在一开始将其转换为字典。好像变量被强制转换为AnyObject一样，编译器将继续提示错误，因为它无法处理它(对于您而言，AnyObject类没有valueForKey函数)。