Swift 中的重命名问题

我是第一次使用 Swift 进行编程，在此过程中我遵循this教程。不幸的是，该教程看起来有点过时，并且大多数代码都会引发构建时错误。最常出现的错误是NSURLSession has been renamed to URLSession。我试过让 Swift 修复它，但在很多情况下它只是开始抛出警告。我也收到了Value type HomeModel has no member'parseJSON'错误以及NSDat is not implicitly convertible to data错误。据我所知， NSURL 似乎已不再使用，但我不确定其他两个。看到这是我从事的第一个 Swift 项目，我不知道如何解决这些问题。有人可以提供一些有关如何修复这些错误的见解吗？

这是代码：

import Foundation

protocol HomeModelProtocal: class {
    func itemsDownloaded(items: NSArray)
}


class HomeModel: NSObject, NSURLSessionDataDelegate {

    //properties

    weak var delegate: HomeModelProtocal!

    var data : NSMutableData = NSMutableData()

    let urlPath: String = "http://testurl.com/service.php" //this will be changed to the path where service.php lives


    func downloadItems() {

        let url: NSURL = NSURL(string: urlPath)!
        var session: NSURLSession!
        let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()


        session = NSURLSession(configuration: configuration, delegate: self, delegateQueue: nil)

        let task = session.dataTaskWithURL(url)

        task.resume()

    }

    func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
        self.data.appendData(data);

    }

    func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?) {
        if error != nil {
            print("Failed to download data")
        }else {
            print("Data downloaded")
            self.parseJSON()
        }

    }
}

在 Swift 3.0 中，一些基本类型已经删除了“NS”前缀。在 swift 2.2 的早期，我们曾经有NSUserDefaults, NSURLSession, NSFileManager现在，他们中的大多数都放弃了前缀“NS”并更改为UserDefaults, URLSession, FileManager etc.

您的代码包含许多带有“NS”前缀的类型。只需删除它，您的代码就可以转换为 Swift 3。转换后的代码如下所示：

protocol HomeModelProtocal: class {
   func itemsDownloaded(items: NSArray)
}

class HomeModel: NSObject, URLSessionDataDelegate {

   //properties

   weak var delegate: HomeModelProtocal!

   var data : Data = Data()

   let urlPath: String = "http://testurl.com/service.php" //this will be changed to the path where service.php lives


   func downloadItems() {

      let url: URL = URL(string: urlPath)!
      var session: URLSession!
      let configuration = URLSessionConfiguration.default

      session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)

      let task = session.dataTask(with: url)

      task.resume()
   }

   func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
       self.data.append(data);
   }

   func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
       if error != nil {
          print("Failed to download data")
       }else {
          print("Data downloaded")
          self.parseJSON() // This class doesn't have a function parseJSON(). So, it's giving you an error like this
       }
   }
}

另外，我没有看到任何调用的函数parseJSON()在你的班级里。我相信你必须添加它。