appendAttributedString類型的返回值void

Question

我試圖追加兩個NSAttributedString。

let string_1 : NSAttributedString = self.answerTextView.attributedText 
let string_2 : NSAttributedString = handleHtml(i) // a function that returns a NSAttributedString 
let finalStr : NSAttributedString = string_1.mutableCopy().appendAttributedString(string_2) 

但我在第三行得到了一個錯誤：

無法將類型的價值 '無效'（又名 '（）'）到指定的類型 'NSAttributedString'

我該如何解決這個問題？謝謝

Answer 1

appendAttributedString更新調用者。它不返回一個新的字符串。請嘗試以下操作：

let string_1 : NSAttributedString = self.answerTextView.attributedText 
let string_2 : NSAttributedString = handleHtml(i) // a function that returns a NSAttributedString 
let tmpStr : NSMutableAttributedString = string_1.mutableCopy() 
tmpStr.appendAttributedString(string_2) 
let finalStr : NSAttributedString = tmpStr.copy() 

Answer 2

防守效率是這樣的：

//MARK: Custom functions 
func getQueueAttributedString(number N: Int) -> NSAttributedString? { 

    let uploadSymbolAttributes = [NSForegroundColorAttributeName: UEColor.brown.six, NSFontAttributeName: UEFont.unearthCharacterFont(13)] 

    let attributedString = NSMutableAttributedString(string: UEFontCharacter.triangle_up, attributes: uploadSymbolAttributes) 

    let queueAttributes = [NSForegroundColorAttributeName: UEColor.brown.six, NSFontAttributeName: UEFont.museo300(withSize: 13)] 

    let queueString = NSAttributedString(string: " \(N) items queued", attributes: queueAttributes) 

    attributedString.append(queueString) 

    return attributedString 

} 

凡UEFont是一個自定義UIFont，UEColor是定製UIColor的靜態結構和UEFontCharacter是線性圖標字體。