How do you use NSAttributedString?

I think, it is a very convenient way to use regular expressions to find a range for applying attributes. This is how I did it:

NSMutableAttributedString *goodText = [[NSMutableAttributedString alloc] initWithString:articleText];

NSRange range = [articleText rangeOfString:@"\\[.+?\\]" options:NSRegularExpressionSearch|NSCaseInsensitiveSearch];
if (range.location != NSNotFound) {
    [goodText addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Georgia" size:16] range:range];
    [goodText addAttribute:NSForegroundColorAttributeName value:[UIColor brownColor] range:range];
}

NSString *regEx = [NSString stringWithFormat:@"%@.+?\\s", [self.article.titleText substringToIndex:0]];
range = [articleText rangeOfString:regEx options:NSRegularExpressionSearch|NSCaseInsensitiveSearch];
if (range.location != NSNotFound) {
    [goodText addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Georgia-Bold" size:20] range:range];
    [goodText addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:range];
}

[self.textView setAttributedText:goodText];

I was searching for a list of available attributes and didn't find them here and in a class reference's first page. So I decided to post here information on that.

Standard Attributes

Attributed strings support the following standard attributes for text. If the key is not in the dictionary, then use the default values described below.

NSString *NSFontAttributeName;
NSString *NSParagraphStyleAttributeName;
NSString *NSForegroundColorAttributeName;
NSString *NSUnderlineStyleAttributeName;
NSString *NSSuperscriptAttributeName;
NSString *NSBackgroundColorAttributeName;
NSString *NSAttachmentAttributeName;
NSString *NSLigatureAttributeName;
NSString *NSBaselineOffsetAttributeName;
NSString *NSKernAttributeName;
NSString *NSLinkAttributeName;
NSString *NSStrokeWidthAttributeName;
NSString *NSStrokeColorAttributeName;
NSString *NSUnderlineColorAttributeName;
NSString *NSStrikethroughStyleAttributeName;
NSString *NSStrikethroughColorAttributeName;
NSString *NSShadowAttributeName;
NSString *NSObliquenessAttributeName;
NSString *NSExpansionAttributeName;
NSString *NSCursorAttributeName;
NSString *NSToolTipAttributeName;
NSString *NSMarkedClauseSegmentAttributeName;
NSString *NSWritingDirectionAttributeName;
NSString *NSVerticalGlyphFormAttributeName;
NSString *NSTextAlternativesAttributeName;

NSAttributedString programming guide

A full class reference is here.

When building attributed strings, I prefer to use the mutable subclass, just to keep things cleaner.

That being said, here's how you create a tri-color attributed string:

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"firstsecondthird"];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(5,6)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(11,5)];

_{typed in a browser. caveat implementor}

Obviously you're not going to hard-code in the ranges like this. Perhaps instead you could do something like:

NSDictionary *wordToColorMapping = ....;  //an NSDictionary of NSString => UIColor pairs
NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@""];
for (NSString *word in wordToColorMapping) {
  UIColor *color = [wordToColorMapping objectForKey:word];
  NSDictionary *attributes = [NSDictionary dictionaryWithObject:color forKey:NSForegroundColorAttributeName];
  NSAttributedString *subString = [[NSAttributedString alloc] initWithString:word attributes:attributes];
  [string appendAttributedString:subString];
  [subString release];
}

//display string

The question is already answered... but I wanted to show how to add shadow and change the font with NSAttributedString as well, so that when people search for this topic they won't have to keep looking.

#define FONT_SIZE 20
#define FONT_HELVETICA @"Helvetica-Light"
#define BLACK_SHADOW [UIColor colorWithRed:40.0f/255.0f green:40.0f/255.0f blue:40.0f/255.0f alpha:0.4f]

NSString*myNSString = @"This is my string.\nIt goes to a second line.";                

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
               paragraphStyle.alignment = NSTextAlignmentCenter;
             paragraphStyle.lineSpacing = FONT_SIZE/2;
                     UIFont * labelFont = [UIFont fontWithName:FONT_HELVETICA size:FONT_SIZE];
                   UIColor * labelColor = [UIColor colorWithWhite:1 alpha:1];
                       NSShadow *shadow = [[NSShadow alloc] init];
                 [shadow setShadowColor : BLACK_SHADOW];
                [shadow setShadowOffset : CGSizeMake (1.0, 1.0)];
            [shadow setShadowBlurRadius : 1];

NSAttributedString *labelText = [[NSAttributedString alloc] initWithString : myNSString
                      attributes : @{
   NSParagraphStyleAttributeName : paragraphStyle,
             NSKernAttributeName : @2.0,
             NSFontAttributeName : labelFont,
  NSForegroundColorAttributeName : labelColor,
           NSShadowAttributeName : shadow }];

Here is a Swift version...

Warning! This works for 4s.

For 5s you have to change all of the the Float values to Double values (because the compiler isn't working correctly yet)

Swift enum for font choice:

enum FontValue: Int {
    case FVBold = 1 , FVCondensedBlack, FVMedium, FVHelveticaNeue, FVLight, FVCondensedBold, FVLightItalic, FVUltraLightItalic, FVUltraLight, FVBoldItalic, FVItalic
}

Swift array for enum access (needed because enum can't use '-'):

func helveticaFont (index:Int) -> (String) {
    let fontArray = [
    "HelveticaNeue-Bold",
    "HelveticaNeue-CondensedBlack",
    "HelveticaNeue-Medium",
    "HelveticaNeue",
    "HelveticaNeue-Light",
    "HelveticaNeue-CondensedBold",
    "HelveticaNeue-LightItalic",
    "HelveticaNeue-UltraLightItalic",
    "HelveticaNeue-UltraLight",
    "HelveticaNeue-BoldItalic",
    "HelveticaNeue-Italic",
    ]
    return fontArray[index]
}

Swift attributed text function:

func myAttributedText (myString:String, mySize: Float, myFont:FontValue) -> (NSMutableAttributedString) {

    let shadow = NSShadow()
    shadow.shadowColor = UIColor.textShadowColor()
    shadow.shadowOffset = CGSizeMake (1.0, 1.0)
    shadow.shadowBlurRadius = 1

    let paragraphStyle = NSMutableParagraphStyle.alloc()
    paragraphStyle.lineHeightMultiple = 1
    paragraphStyle.lineBreakMode = NSLineBreakMode.ByWordWrapping
    paragraphStyle.alignment = NSTextAlignment.Center

    let labelFont = UIFont(name: helveticaFont(myFont.toRaw()), size: mySize)
    let labelColor = UIColor.whiteColor()

    let myAttributes :Dictionary = [NSParagraphStyleAttributeName : paragraphStyle,
                                              NSKernAttributeName : 3, // (-1,5)
                                              NSFontAttributeName : labelFont,
                                   NSForegroundColorAttributeName : labelColor,
                                            NSShadowAttributeName : shadow]

    let myAttributedString = NSMutableAttributedString (string: myString, attributes:myAttributes)

    // add new color 
    let secondColor = UIColor.blackColor()
    let stringArray = myString.componentsSeparatedByString(" ")
    let firstString: String? = stringArray.first
    let letterCount = countElements(firstString!)
    if firstString {
        myAttributedString.addAttributes([NSForegroundColorAttributeName:secondColor], range:NSMakeRange(0,letterCount))
    }

    return  myAttributedString
}

first and last extension used for finding ranges in a string array:

extension Array {
    var last: T? {
        if self.isEmpty {
            NSLog("array crash error - please fix")
            return self [0]
        } else {
            return self[self.endIndex - 1]
        }
    }
}

extension Array {
    var first: T? {
        if self.isEmpty {
            NSLog("array crash error - please fix")
            return self [0]
        } else {
            return self [0]
        }
    }
}

new colors:

extension UIColor {
    class func shadowColor() -> UIColor {
        return UIColor(red: 0.0/255.0, green: 0.0/255.0, blue: 0.0/255.0, alpha: 0.3)
    }
    class func textShadowColor() -> UIColor {
        return UIColor(red: 50.0/255.0, green: 50.0/255.0, blue: 50.0/255.0, alpha: 0.5)
    }
    class func pastelBlueColor() -> UIColor {
        return UIColor(red: 176.0/255.0, green: 186.0/255.0, blue: 255.0/255.0, alpha: 1)
    }
    class func pastelYellowColor() -> UIColor {
        return UIColor(red: 255.0/255.0, green: 238.0/255.0, blue: 140.0/255.0, alpha: 1)
    }
}

my macro replacement:

enum MyConstants: Float {
    case CornerRadius = 5.0
}

my button maker w/attributed text:

func myButtonMaker (myView:UIView) -> UIButton {

    let myButton = UIButton.buttonWithType(.System) as UIButton
    myButton.backgroundColor = UIColor.pastelBlueColor()
    myButton.showsTouchWhenHighlighted = true;
    let myCGSize:CGSize = CGSizeMake(100.0, 50.0)
    let myFrame = CGRectMake(myView.frame.midX - myCGSize.height,myView.frame.midY - 2 * myCGSize.height,myCGSize.width,myCGSize.height)
    myButton.frame = myFrame
    let myTitle = myAttributedText("Button",20.0,FontValue.FVLight)
    myButton.setAttributedTitle(myTitle, forState:.Normal)

    myButton.layer.cornerRadius = myButton.bounds.size.width / MyConstants.CornerRadius.toRaw()
    myButton.setTitleColor(UIColor.whiteColor(), forState: .Normal)
    myButton.tag = 100
    myButton.bringSubviewToFront(myView)
    myButton.layerGradient()

    myView.addSubview(myButton)

    return  myButton
}

my UIView/UILabel maker w/attributed text, shadow, and round corners:

func myLabelMaker (myView:UIView) -> UIView {

    let myFrame = CGRectMake(myView.frame.midX / 2 , myView.frame.midY / 2, myView.frame.width/2, myView.frame.height/2)
    let mylabelFrame = CGRectMake(0, 0, myView.frame.width/2, myView.frame.height/2)

    let myBaseView = UIView()
    myBaseView.frame = myFrame
    myBaseView.backgroundColor = UIColor.clearColor()

    let myLabel = UILabel()
    myLabel.backgroundColor=UIColor.pastelYellowColor()
    myLabel.frame = mylabelFrame

    myLabel.attributedText = myAttributedText("This is my String",20.0,FontValue.FVLight)
    myLabel.numberOfLines = 5
    myLabel.tag = 100
    myLabel.layer.cornerRadius = myLabel.bounds.size.width / MyConstants.CornerRadius.toRaw()
    myLabel.clipsToBounds = true
    myLabel.layerborders()

    myBaseView.addSubview(myLabel)

    myBaseView.layerShadow()
    myBaseView.layerGradient()

    myView.addSubview(myBaseView)

    return myLabel
}

generic shadow add:

func viewshadow<T where T: UIView> (shadowObject: T)
{
    let layer = shadowObject.layer
    let radius = shadowObject.frame.size.width / MyConstants.CornerRadius.toRaw();
    layer.borderColor = UIColor.whiteColor().CGColor
    layer.borderWidth = 0.8
    layer.cornerRadius = radius
    layer.shadowOpacity = 1
    layer.shadowRadius = 3
    layer.shadowOffset = CGSizeMake(2.0,2.0)
    layer.shadowColor = UIColor.shadowColor().CGColor
}

view extension for view style:

extension UIView {
    func layerborders() {
        let layer = self.layer
        let frame = self.frame
        let myColor = self.backgroundColor
        layer.borderColor = myColor.CGColor
        layer.borderWidth = 10.8
        layer.cornerRadius = layer.borderWidth / MyConstants.CornerRadius.toRaw()
    }

    func layerShadow() {
        let layer = self.layer
        let frame = self.frame
        layer.cornerRadius = layer.borderWidth / MyConstants.CornerRadius.toRaw()
        layer.shadowOpacity = 1
        layer.shadowRadius = 3
        layer.shadowOffset = CGSizeMake(2.0,2.0)
        layer.shadowColor = UIColor.shadowColor().CGColor
    }

    func layerGradient() {
        let layer = CAGradientLayer()
        let size = self.frame.size
        layer.frame.size = size
        layer.frame.origin = CGPointMake(0.0,0.0)
        layer.cornerRadius = layer.bounds.size.width / MyConstants.CornerRadius.toRaw();

        var color0 = CGColorCreateGenericRGB(250.0/255, 250.0/255, 250.0/255, 0.5)
        var color1 = CGColorCreateGenericRGB(200.0/255, 200.0/255, 200.0/255, 0.1)
        var color2 = CGColorCreateGenericRGB(150.0/255, 150.0/255, 150.0/255, 0.1)
        var color3 = CGColorCreateGenericRGB(100.0/255, 100.0/255, 100.0/255, 0.1)
        var color4 = CGColorCreateGenericRGB(50.0/255, 50.0/255, 50.0/255, 0.1)
        var color5 = CGColorCreateGenericRGB(0.0/255, 0.0/255, 0.0/255, 0.1)
        var color6 = CGColorCreateGenericRGB(150.0/255, 150.0/255, 150.0/255, 0.1)

        layer.colors = [color0,color1,color2,color3,color4,color5,color6]
        self.layer.insertSublayer(layer, atIndex: 2)
    }
}

the actual view did load function:

func buttonPress (sender:UIButton!) {
    NSLog("%@", "ButtonPressed")
}

override func viewDidLoad() {
    super.viewDidLoad()

    let myLabel = myLabelMaker(myView)
    let myButton = myButtonMaker(myView)

    myButton.addTarget(self, action: "buttonPress:", forControlEvents:UIControlEvents.TouchUpInside)

    viewshadow(myButton)
    viewshadow(myLabel)

}

This solution will work for any length

NSString *strFirst = @"Anylengthtext";
NSString *strSecond = @"Anylengthtext";
NSString *strThird = @"Anylengthtext";

NSString *strComplete = [NSString stringWithFormat:@"%@ %@ %@",strFirst,strSecond,strThird];

NSMutableAttributedString *attributedString =[[NSMutableAttributedString alloc] initWithString:strComplete];

[attributedString addAttribute:NSForegroundColorAttributeName
              value:[UIColor redColor]
              range:[strComplete rangeOfString:strFirst]];

[attributedString addAttribute:NSForegroundColorAttributeName
              value:[UIColor yellowColor]
              range:[strComplete rangeOfString:strSecond]];

[attributedString addAttribute:NSForegroundColorAttributeName
              value:[UIColor blueColor]
              range:[strComplete rangeOfString:strThird]];


self.lblName.attributedText = attributedString;