值類型「字符串」沒有成員「stringByTrimmingCharactersInSet」

Question

我的項目轉換爲SWIFT 3之後，我得到下面的這個區塊內的第一行Value of type 'String' has no member 'stringByTrimmingCharactersInSet'錯誤：

extension UIColor { 
    convenience init (hex:String) { 
     var cString:String = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercased() // error appears on this line 

     if (cString.hasPrefix("#")) { 
      cString = (cString as NSString).substring(from: 1) 
     } 



     let rString = (cString as NSString).substring(to: 2) 
     let gString = ((cString as NSString).substring(from: 2) as NSString).substring(to: 2) 
     let bString = ((cString as NSString).substring(from: 4) as NSString).substring(to: 2) 

     var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0; 
     Scanner(string: rString).scanHexInt32(&r) 
     Scanner(string: gString).scanHexInt32(&g) 
     Scanner(string: bString).scanHexInt32(&b) 


     self.init(red: CGFloat(r)/255.0, green: CGFloat(g)/255.0, blue: CGFloat(b)/255.0, alpha: CGFloat(1)) 
    } 
} 

我猜錯誤從'stringByTrimmingCharactersInSet'的語法變化中得到。這是什麼修正？

Answer 1

新的語法是這樣的：

var cString = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased() 

作爲一個建議，你並不需要指定cString是一個字符串，因爲這是假設你分配給它的值。

Answer 2

閱讀Swift 3文檔;新雨燕3 API是：

func trimmingCharacters(in set: CharacterSet) -> String 

https://developer.apple.com/reference/swift/string/1643030-trimmingcharacters

Answer 3

你也可以試試這個。

let trimmedString = hex.trimmingCharacters(in: CharacterSet.whitespaces)