在将json和HTTP“post”代码转换为Swift时出错3

Question

我想从教程中将旧代码转换为Swift 3，因为此刻我正在处理的项目已经在Swift 3中。我无法发送POST请求并阅读我收到的JSON。请注意，这些截图是从视频中截取的，因此有可能重复某些代码。

我的代码如下：

let myURL = NSURL(string:"http://localhost/bahApp/scripts/registerUser.php?"); 
    let request = NSMutableURLRequest(url:myURL as! URL) 
    request.httpMethod = "POST"; 
    let postString = "userEmail=\(userEmail)&userPassword=\(userPassword)&userFirstName=\(userFirstName)&userLastName=\(userLastName)&numberOfConnections=\(numberOfConnections)&installerID=\(installerID)" 
    request.httpBody = postString.data(using: String.Encoding.utf8); 

    let task = URLSession.shared.dataTask(with: myURL as URL!) { data, response, error in 
     DispatchQueue.main.async { 
      if error != nil{ 
      self.displayAlertMessage(userMessage: (error?.localizedDescription)!) 
       return 
      } 
      do { 
       if let jsonResult = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String:Any] 
       {print(jsonResult)} 

      } catch let error as NSError { 
       print(error.localizedDescription) 
      } 

      let parseJSON = jsonResult as? NSDictionary { 

       var userId = parseJSON["userID"] as? String 

      if (userId != nil){ 
       var myAlert = UIAlertController(title: "Alert", message: "registration successful", preferredStyle: UIAlertControllerStyle.alert) 
       let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil) 
       myAlert.addAction(okAction); 
       self.present(myAlert, animated: true, completion: nil) 
      }else{ 
       let errorMessage = parseJSON["message"] as? String 
       if (errorMessage != nil){ 
       self.displayAlertMessage(userMessage: errorMessage!) 
       } 
       } 
      } 
     } 
    } 
    task.resume() 
} 

func displayAlertMessage(userMessage: String){ 

    var myAlert = UIAlertController(title: "Alert", message: userMessage, preferredStyle: UIAlertControllerStyle.alert) 
    let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil) 
    myAlert.addAction(okAction); 
    self.present(myAlert, animated: true, completion: nil) 

我想知道有没有正确地转换大部分代码，以及如何解决这些错误所看到在下面的截图中：

我已经广泛搜查这一点，只有能对大家有点帮助的职位是this post

Answer 1

你的代码试图使用被访问的范例以外的实例。这是因为do块内的声明而发生的。试试下面的代码：

let task = URLSession.shared.dataTask(with: myURL as URL!) { data, response, error in 
    DispatchQueue.main.async { 
     if let error = error { 
      self.displayAlertMessage(userMessage:(error.localizedDescription)!) 
      return 
     } 

     let jsonResult: [String:Any]? 
     do { 
      jsonResult = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String:Any] 
      if let result = jsonResult { 
       print(result) 
      } 

     } catch let error as NSError { 
      print(error.localizedDescription) 
     } 

     if let parseJSON = jsonResult as? NSDictionary { 

      if let userId = parseJSON["userID"] as? String { 
       var myAlert = UIAlertController(title: "Alert", message: "registration successful", preferredStyle: UIAlertControllerStyle.alert) 
       let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil) 
       myAlert.addAction(okAction); 
       self.present(myAlert, animated: true, completion: nil) 
      } else { 
       if let errorMessage = parseJSON["message"] as? String 
        self.displayAlertMessage(userMessage: errorMessage!) 
       } 
      } 
     } 
    } 
} 

Answer 2

你忘了let parseJSON之前添加if。

if let parseJSON = jsonResult as? NSDictionary { 
    //... 
}