Replace substring of NSAttributedString with another NSAttributedString

Question

I want to replace a substring (e.g. @\"replace\") of an NSAttributedString with another NSAttributedString.

I am looking for a

Answer 1

Swift 4: Updated sunkas excellent solution to Swift 4 and wrapped in "extension". Just clip this into your ViewController (outside the class) and use it.

extension NSAttributedString {
    func stringWithString(stringToReplace: String, replacedWithString newStringPart: String) -> NSMutableAttributedString
    {
        let mutableAttributedString = mutableCopy() as! NSMutableAttributedString
        let mutableString = mutableAttributedString.mutableString
        while mutableString.contains(stringToReplace) {
            let rangeOfStringToBeReplaced = mutableString.range(of: stringToReplace)
            mutableAttributedString.replaceCharacters(in: rangeOfStringToBeReplaced, with: newStringPart)
        }
        return mutableAttributedString
    }
}

Answer 2

Here is how you can change the string of NSMutableAttributedString, while preserving its attributes:

Swift:

// first we create a mutable copy of attributed text 
let originalAttributedText = nameLabel.attributedText?.mutableCopy() as! NSMutableAttributedString

// then we replace text so easily
let newAttributedText = originalAttributedText.mutableString.setString("new text to replace")

Objective-C:

NSMutableAttributedString *newAttrStr = [attribtedTxt.mutableString setString:@"new string"];

Answer 3

1. Convert your attributed string into an instance of NSMutableAttributedString.

2. The mutable attributed string has a mutableString property. According to the documentation:

   "The receiver tracks changes to this string and keeps its attribute mappings up to date."

   So you can use the resulting mutable string to execute the replacement with replaceOccurrencesOfString:withString:options:range:.

Answer 4

I have a specific requirement and fixed like below. This might help someone.

Requirement: In the storyboard, rich text directly added to UITextView's attribute which contains a word "App Version: 1.0". Now I have to dynamise the version number by reading it from info plist.

Solution: Deleted version number 1.0 from the storyboard, just kept "App Version:" and added below code.

NSAttributedString *attribute = self.firsttextView.attributedText;
NSMutableAttributedString *mutableAttri = [[NSMutableAttributedString alloc] initWithAttributedString:attribute];
NSString *appVersionText = @"App Version:";
if ([[mutableAttri mutableString] containsString:appVersionText]) {
    NSDictionary* infoDict = [[NSBundle mainBundle] infoDictionary];
    NSString* version = [infoDict objectForKey:@"CFBundleShortVersionString"];
    NSString *newappversion = [NSString stringWithFormat:@"%@ %@",appVersionText,version] ;
    [[mutableAttri mutableString] replaceOccurrencesOfString:appVersionText withString:newappversion options:NSCaseInsensitiveSearch range:NSMakeRange(0, mutableAttri.length)];
    self.firsttextView.attributedText = mutableAttri;
}

Done!! Updated/modified attributedText.

Answer 5

NSMutableAttributedString *result = [[NSMutableAttributedString alloc] initWithString:@"I am a boy."];
[result addAttribute:NSForegroundColorAttributeName value:[UIColor blackColor] range:NSMakeRange(0, [result length])];

NSMutableAttributedString *replace = [[NSMutableAttributedString alloc] initWithString:@"a"];
[replace addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, [replace length])];

[result replaceCharactersInRange:NSMakeRange(5, [replace length]) withAttributedString:replace];

Answer 6

In my case, the following way was the only (tested on iOS9):

NSAttributedString *attributedString = ...;
NSAttributedString *anotherAttributedString = ...; //the string which will replace

while ([attributedString.mutableString containsString:@"replace"]) {
        NSRange range = [attributedString.mutableString rangeOfString:@"replace"];
        [attributedString replaceCharactersInRange:range  withAttributedString:anotherAttributedString];
    }

Of course it will be nice to find another better way.