Xcode错误对成员'dataTask的歧义引用（with：completionHandler :)'

Question

我有一个swift 2.3项目，我刚更新到swift 3.0，下面的代码破坏了。

let task = URLSession.shared.dataTask(with: request, completionHandler: { 
     data, response, error in 

     if error != nil { 
      print("error=\(error)") 
      return 
     } 

     print("response = \(response)") 

     let responseString = NSString(data: data!, encoding: String.Encoding.utf8) 
     print("responseString = \(responseString)") 
    }) 
    task.resume() 

，我不知道如何解决它

Answer 1

你可以得到错误，如果request是NSURLRequest而非URLRequest。

let url = URL(string: urlString)! 
let request = URLRequest(url: url) 

let task = URLSession.shared.dataTask(with: request) { data, response, error in 
    guard let data = data, error == nil else { 
     print("error=\(error)") 
     return 
    } 

    print("response = \(response)") 

    let responseString = String(data: data, encoding: .utf8) 
    print("responseString = \(responseString)") 
} 
task.resume() 

或者，如果你的变异URLRequest，使用var：

let url = URL(string: urlString)! 
var request = URLRequest(url: url) 
request.httpMethod = "POST" 
request.httpBody = ... 

let task = URLSession.shared.dataTask(with: request) { data, response, error in 
    guard let data = data, error == nil else { 
     print("error=\(error)") 
     return 
    } 

    print("response = \(response)") 

    let responseString = String(data: data, encoding: .utf8) 
    print("responseString = \(responseString)") 
} 
task.resume() 

此外，请注意，我把它换成NSString与String。