How do you use NSAttributedString?

Question

Multiple colours in an NSString or NSMutableStrings are not possible. So I\'ve heard a little about the NSAttributedString which was introduced wit

Answer 1

You can load an HTML attributed string in Swift as follow

   var Str = NSAttributedString(
   data: htmlstring.dataUsingEncoding(NSUnicodeStringEncoding, allowLossyConversion: true),
   options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
   documentAttributes: nil,
   error: nil)

   label.attributedText = Str  

To load a html from file

   if let rtf = NSBundle.mainBundle().URLForResource("rtfdoc", withExtension: "rtf", subdirectory: nil, localization: nil) {

   let attributedString = NSAttributedString(fileURL: rtf, options: [NSDocumentTypeDocumentAttribute:NSRTFTextDocumentType], documentAttributes: nil, error: nil)
        textView.attributedText = attributedString
        textView.editable = false
    }

http://sketchytech.blogspot.in/2013/11/creating-nsattributedstring-from-html.html

And setup string as per your required attribute....follow this..
http://makeapppie.com/2014/10/20/swift-swift-using-attributed-strings-in-swift/

Answer 2

I wrote helper to add attributes easily:

- (void)addColor:(UIColor *)color substring:(NSString *)substring;
- (void)addBackgroundColor:(UIColor *)color substring:(NSString *)substring;
- (void)addUnderlineForSubstring:(NSString *)substring;
- (void)addStrikeThrough:(int)thickness substring:(NSString *)substring;
- (void)addShadowColor:(UIColor *)color width:(int)width height:(int)height radius:(int)radius substring:(NSString *)substring;
- (void)addFontWithName:(NSString *)fontName size:(int)fontSize substring:(NSString *)substring;
- (void)addAlignment:(NSTextAlignment)alignment substring:(NSString *)substring;
- (void)addColorToRussianText:(UIColor *)color;
- (void)addStrokeColor:(UIColor *)color thickness:(int)thickness substring:(NSString *)substring;
- (void)addVerticalGlyph:(BOOL)glyph substring:(NSString *)substring;

https://github.com/shmidt/MASAttributes

You can install through CocoaPods also : pod 'MASAttributes', '~> 1.0.0'

Answer 3

An easier solution with attributed string extension.

extension NSMutableAttributedString {

    // this function attaches color to string    
    func setColorForText(textToFind: String, withColor color: UIColor) {
        let range: NSRange = self.mutableString.range(of: textToFind, options: .caseInsensitive)
        self.addAttribute(NSAttributedStringKey.foregroundColor, value: color, range: range)
    }

}

Try this and see (Tested in Swift 3 & 4)

let label = UILabel()
label.frame = CGRect(x: 120, y: 100, width: 200, height: 30)
let first = "first"
let second = "second"
let third = "third"
let stringValue = "\(first)\(second)\(third)"  // or direct assign single string value like "firstsecondthird"

let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: stringValue)
attributedString.setColorForText(textToFind: first, withColor: UIColor.red)   // use variable for string "first"
attributedString.setColorForText(textToFind: "second", withColor: UIColor.green) // or direct string like this "second"
attributedString.setColorForText(textToFind: third, withColor: UIColor.blue)
label.font = UIFont.systemFont(ofSize: 26)
label.attributedText = attributedString
self.view.addSubview(label)

Here is expected result:

Answer 4

Super easy way to do this.

let text = "This is a colorful attributed string"
let attributedText = 
NSMutableAttributedString.getAttributedString(fromString: text)
attributedText.apply(color: .red, subString: "This")
//Apply yellow color on range
attributedText.apply(color: .yellow, onRange: NSMakeRange(5, 4))

For more detail click here; https://github.com/iOSTechHub/AttributedString

Answer 5

To solve such kind of problems I created library in swift which is called Atributika.

let str = "<r>first</r><g>second</g><b>third</b>".style(tags:
        Style("r").foregroundColor(.red),
        Style("g").foregroundColor(.green),
        Style("b").foregroundColor(.blue)).attributedString

label.attributedText = str

You can find it here https://github.com/psharanda/Atributika

Answer 6

I made a library that makes this a lot easier. Check out ZenCopy.

You can create Style objects, and/or set them to keys to reference later. Like this:

ZenCopy.manager.config.setStyles {
    return [
        "token": Style(
            color: .blueColor(), // optional
            // fontName: "Helvetica", // optional
            fontSize: 14 // optional
        )
    ]
}

Then, you can easily construct strings AND style them AND have params :)

label.attributedText = attributedString(
                                ["$0 ".style("token") "is dancing with ", "$1".style("token")], 
                          args: ["JP", "Brock"]
)

You can also style things easily with regex searches!

let atUserRegex = "(@[A-Za-z0-9_]*)"
mutableAttributedString.regexFind(atUserRegex, addStyle: "token")

This will style all words with '@' in front of it with the 'token' style. (e.g. @jpmcglone)

I need to still get it working w/ everything NSAttributedString has to offer, but I think fontName, fontSize and color cover the bulk of it. Expect lots of updates soon :)

I can help you get started with this if you need. Also looking for feedback, so if it makes your life easier, I'd say mission accomplished.