ios - Swift NSAttributedString 修剪

Question

我想去掉 NSAttributedString(Trimming it) 前面和结尾的空白。我不能简单地将它转换为字符串并进行修剪，因为其中有图像(附件)。我该怎么做？

Answer 1

如下所示创建 NSAttributedString 的扩展。

extension NSAttributedString {
     public func attributedStringByTrimmingCharacterSet(charSet: CharacterSet) -> NSAttributedString {
         let modifiedString = NSMutableAttributedString(attributedString: self)
        modifiedString.trimCharactersInSet(charSet: charSet)
         return NSAttributedString(attributedString: modifiedString)
     }
}

extension NSMutableAttributedString {
     public func trimCharactersInSet(charSet: CharacterSet) {
        var range = (string as NSString).rangeOfCharacter(from: charSet as CharacterSet)

         // Trim leading characters from character set.
         while range.length != 0 && range.location == 0 {
            replaceCharacters(in: range, with: "")
            range = (string as NSString).rangeOfCharacter(from: charSet)
         }

         // Trim trailing characters from character set.
        range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
         while range.length != 0 && NSMaxRange(range) == length {
            replaceCharacters(in: range, with: "")
            range = (string as NSString).rangeOfCharacter(from: charSet, options: .backwards)
         }
     }
}

并在您要使用的 viewController 中使用。像这样

let attstring = NSAttributedString(string: "this is test message. Please wait.                   ")
let result = attstring.attributedStringByTrimmingCharacterSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())