崩溃的NSAttributedString

Question

替换字符的任何想法，为什么这种崩溃：

extension NSAttributedString { 

    func replaceCharacters(inRange: NSRange, withString: String) -> NSAttributedString { 
     let mutableString = mutableCopy() as! NSMutableAttributedString 
     mutableString.replaceCharacters(in: inRange, with: withString) 
     return mutableString 
    } 

} 

let label = UILabel() 
label.attributedText = NSAttributedString(string: "abcdef") 
let string = label.attributedText?.replaceCharacters(inRange: NSRange(location: 1, length: 1), withString: "-") 

但是，这不？

let label = UILabel() 
label.attributedText = NSAttributedString(string: "abcdef") 

let mutableString = label.attributedText?.mutableCopy() as! NSMutableAttributedString 
mutableString.replaceCharacters(in: NSRange(location: 1, length: 1), with: "-") 
let string: NSAttributedString = mutableString 

PS：首先，我对第二要点做的是代码从replaceCharacters(inRange:withString:)内从第一要点复制。

Answer 1

试试这个：

extension String { 
    func replaceCharacters(withString: String) -> NSAttributedString { 

     var range = (self as NSString).range(of: withString) 
     let attributedString = NSMutableAttributedString(string:self) 
     attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.black, range: range) 
     if let font = UIFont(name: "Helvetica Bold", size: 14) { 
      attributedString.addAttribute(NSFontAttributeName, value: font, range: range) 
     } 
     return attributedString 
    } 
} 

let label = UILabel() 
label.attributedText = "pqr abcdefg xyz".replaceCharacters("abc") 

注：请字符串的addAttribute按您的要求

Answer 2

试试这个，这将帮助你

斯威夫特3：

let label = UILabel() 
    override func viewDidLoad() { 
     super.viewDidLoad() 

     let attrString = NSMutableAttributedString(string: "abcdef") 
     attrString.mutableString.replaceCharacters(in: NSRange(location: 1, length: 1), with: "-") 

     label.attributedText = NSAttributedString(string: attrString.string) 
     print(label.attributedText!) 

    }