How can I concatenate NSAttributedStrings?

Question

I need to search some strings and set some attributes prior to merging the strings, so having NSStrings -> Concatenate them -> Make NSAttributedString is not an option, is there any way to concatenate attributedString to another attributedString?

Answer 1

I'd recommend you use a single mutable attributed string a @Linuxios suggested, and here's another example of that:

NSMutableAttributedString *mutableAttString = [[NSMutableAttributedString alloc] init];

NSString *plainString = // ...
NSDictionary *attributes = // ... a dictionary with your attributes.
NSAttributedString *newAttString = [[NSAttributedString alloc] initWithString:plainString attributes:attributes];

[mutableAttString appendAttributedString:newAttString];

However, just for the sake of getting all the options out there, you could also create a single mutable attributed string, made from a formatted NSString containing the input strings already put together. You could then use addAttributes: range: to add the attributes after the fact to the ranges containing the input strings. I recommend the former way though.

Answer 2

If you're using Swift, you can just overload the + operator so that you can concatenate them in the same way you concatenate normal strings:

// concatenate attributed strings
func + (left: NSAttributedString, right: NSAttributedString) -> NSAttributedString
{
    let result = NSMutableAttributedString()
    result.append(left)
    result.append(right)
    return result
}

Now you can concatenate them just by adding them:

let helloworld = NSAttributedString(string: "Hello ") + NSAttributedString(string: "World")

Answer 3

Swift 3: Simply create a NSMutableAttributedString and append the attributed strings to them.

let mutableAttributedString = NSMutableAttributedString()

let boldAttribute = [
    NSFontAttributeName: UIFont(name: "GothamPro-Medium", size: 13)!,
    NSForegroundColorAttributeName: Constants.defaultBlackColor
]

let regularAttribute = [
    NSFontAttributeName: UIFont(name: "Gotham Pro", size: 13)!,
    NSForegroundColorAttributeName: Constants.defaultBlackColor
]

let boldAttributedString = NSAttributedString(string: "Warning: ", attributes: boldAttribute)
let regularAttributedString = NSAttributedString(string: "All tasks within this project will be deleted.  If you're sure you want to delete all tasks and this project, type DELETE to confirm.", attributes: regularAttribute)
mutableAttributedString.append(boldAttributedString)
mutableAttributedString.append(regularAttributedString)

descriptionTextView.attributedText = mutableAttributedString

Answer 4

Try this:

NSMutableAttributedString* result = [astring1 mutableCopy];
[result appendAttributedString:astring2];

Where astring1 and astring2 are NSAttributedStrings.

Answer 5

If you're using Cocoapods, an alternative to both above answers that let you avoid mutability in your own code is to use the excellent NSAttributedString+CCLFormat category on NSAttributedStrings that lets you write something like:

NSAttributedString *first = ...;
NSAttributedString *second = ...;
NSAttributedString *combined = [NSAttributedString attributedStringWithFormat:@"%@%@", first, second];

It of course it just uses NSMutableAttributedString under the covers.

It also has the extra advantage of being a fully fledged formatting function — so it can do a lot more than appending strings together.

Answer 6

// Immutable approach
// class method

+ (NSAttributedString *)stringByAppendingString:(NSAttributedString *)append toString:(NSAttributedString *)string {
  NSMutableAttributedString *result = [string mutableCopy];
  [result appendAttributedString:append];
  NSAttributedString *copy = [result copy];
  return copy;
}

//Instance method
- (NSAttributedString *)stringByAppendingString:(NSAttributedString *)append {
  NSMutableAttributedString *result = [self mutableCopy];
  [result appendAttributedString:append];
  NSAttributedString *copy = [result copy];
  return copy;
}

Answer 7

You can try SwiftyFormat It uses following syntax

let format = "#{{user}} mentioned you in a comment. #{{comment}}"
let message = NSAttributedString(format: format,
                                 attributes: commonAttributes,
                                 mapping: ["user": attributedName, "comment": attributedComment])