Swift NSAttributedString Trim

Question

Ich möchte die weißen Felder vor und am Ende meines NSAttributedString (Trimming es) fahren. Ich kann es nicht einfach in eine Zeichenkette umwandeln und trimmen, weil Bilder (Anhänge) darin enthalten sind. Wie kann ich es tun?

Answer 1

Erstellen Sie die Erweiterung NSAttributedString wie folgt.

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

extension NSMutableAttributedString { 
    public func trimCharactersInSet(charSet: NSCharacterSet) { 
     var range = (string as NSString).rangeOfCharacterFromSet(charSet) 

     // Trim leading characters from character set. 
     while range.length != 0 && range.location == 0 { 
      replaceCharactersInRange(range, withString: "") 
      range = (string as NSString).rangeOfCharacterFromSet(charSet) 
     } 

     // Trim trailing characters from character set. 
     range = (string as NSString).rangeOfCharacterFromSet(charSet, options: .BackwardsSearch) 
     while range.length != 0 && NSMaxRange(range) == length { 
      replaceCharactersInRange(range, withString: "") 
      range = (string as NSString).rangeOfCharacterFromSet(charSet, options: .BackwardsSearch) 
     } 
    } 
} 

und verwenden Sie in ViewController, wo Sie verwenden möchten. wie diese

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

Answer 2

Der folgende Code funktioniert für Ihre Anforderung.

var attString: NSAttributedString = NSAttributedString(string: " this is att string") 

let trimmedString = attString.string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet()) 

Answer 3

machte ich eine schnelle 3-Implementierung, falls es jemanden interessiert:

/** 
Trim an attributed string. Can for example be used to remove all leading and trailing spaces and line breaks. 
*/ 
public func attributedStringByTrimmingCharactersInSet(set: CharacterSet) -> NSAttributedString { 
    let invertedSet = set.inverted 
    let rangeFromStart = string.rangeOfCharacter(from: invertedSet) 
    let rangeFromEnd = string.rangeOfCharacter(from: invertedSet, options: .backwards) 
    if let startLocation = rangeFromStart?.upperBound, let endLocation = rangeFromEnd?.lowerBound { 
     let location = string.distance(from: string.startIndex, to: startLocation) - 1 
     let length = string.distance(from: startLocation, to: endLocation) + 2 
     let newRange = NSRange(location: location, length: length) 
     return self.attributedSubstring(from: newRange) 
    } else { 
     return NSAttributedString() 
    } 
} 

Answer 4

Swift 3.2 Version:

extension NSAttributedString { 
    public func trimmingCharacters(in characterSet: CharacterSet) -> NSAttributedString { 
     let modifiedString = NSMutableAttributedString(attributedString: self) 
     modifiedString.trimCharacters(in: characterSet) 
     return NSAttributedString(attributedString: modifiedString) 
    } 
} 

extension NSMutableAttributedString { 
    public func trimCharacters(in characterSet: CharacterSet) { 
     var range = (string as NSString).rangeOfCharacter(from: characterSet) 

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

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