Xcode 8 Swift 3爲什麼generateBoundaryString（）會產生錯誤？

Question

編譯器說該方法是一個未解決的標識符。有什麼問題：var boundary=generateBoundaryString()？

import UIKit 
import Foundation 

class ViewController: UIViewController, 
    UIImagePickerControllerDelegate, 
    UINavigationControllerDelegate 
{ 
    override func viewDidLoad() { 
     super.viewDidLoad() 
    } 

    @IBAction func sendToServer(_ sender: UIButton) { 
     let url = NSURL(string: "http://www.example.com/picSaver.php") 

     var request = URLRequest(url: url! as URL) 
     request.httpMethod = "POST" 
     var boundary = generateBoundaryString() 
    } 

編譯器抱怨generateBoundaryString()是一個未解決的標識符。爲什麼？

Answer 1

generateBoundaryString()函數不是由UIKit定義的，所以需要添加它。

這裏有一個適當的定義添加IBAction如下：

func generateBoundaryString() -> String {  
    return "Boundary-\(NSUUID().uuidString)" 
}