NSAttributedString is pretty rad. When it was ported into iOS 4 from Mac OS, iPhone developers everywhere rejoiced. Unfortunately, as of iOS 4 none of the standard controls in UIKit support it. Bummer.

TTTAttributedLabel was created to be a drop-in replacement for UILabel, that provided a simple API to styling text with NSAttributedString while remaining performant. As a bonus, it also supports link embedding, both automatically with UIDataDetectorTypes and manually by specifying a range for a URL, address, phone number, or event.

Online documentation is available at https://mattt.github.com/TTTAttributedLabel/.

To install the docset directly into your local Xcode organizer, first install appledoc, and then clone this project and run appledoc -p TTTAttributedLabel -c "Mattt Thompson" --company-id com.mattt TTTAttributedLabel.*

Build and run the TTTAttributedLabelExample project in Xcode to see TTTAttributedLabel in action.

TTTAttributedLabel requires the CoreText Framework, so the first thing you'll need to do is include the framework into your project. In Xcode 4, go to the project file at the root of your workspace and select your active target. There should be several sections across the top of that window; choose "Build Phases". Next, click "Link Binary With Libraries" to expand that section to see the frameworks currently included in your project. Click the "+" at the bottom left and select "CoreText.framework".

Now that the framework has been linked, all you need to do is drop TTTAttributedLabel.{h,m} into your project, and add #include "TTTAttributedLabel.h" to the top of classes that will use it.

TTTAttributedLabel *label = [[[TTTAttributedLabel alloc] initWithFrame:CGRectZero] autorelease];
label.font = [UIFont systemFontOfSize:14];
label.textColor = [UIColor darkGrayColor];
label.lineBreakMode = UILineBreakModeWordWrap;
label.numberOfLines = 0;

NSString *text = @"Lorem ipsum dolar sit amet";
[label setText:text afterInheritingLabelAttributesAndConfiguringWithBlock:^ NSAttributedString *(NSMutableAttributedString *mutableAttributedString) {
  NSRange boldRange = [[mutableAttributedString string] rangeOfString:@"ipsum dolar" options:NSCaseInsensitiveSearch];
  
  // Core Text APIs use C functions without a direct bridge to UIFont. See Apple's "Core Text Programming Guide" to learn how to configure string attributes.
  UIFont *boldSystemFont = [UIFont boldSystemFontOfSize:14]; 
	CTFontRef font = CTFontCreateWithName((CFStringRef)boldSystemFont.fontName, boldSystemFont.pointSize, NULL);
	if (font) {
	  [mutableAttributedString addAttribute:(NSString *)kCTFontAttributeName value:(id)font range:boldRange];
	  CFRelease(font);
	}
	
	return mutableAttributedString;
}];

First, we create and configure the label, the same way you would instantiate UILabel. Any text properties that are set on the label are inherited as the base attributes when using the -setText:afterInheritingLabelAttributesAndConfiguringWithBlock: method. In this example, the substring "ipsum dolar", would appear in bold, such that the label would read "Lorem ipsum dolar sit amet", in size 14 Helvetica, with a dark gray color.

The normal setText: setter accepts both NSString and NSAttributedString; in the latter case, the attributed string is directly set, without inheriting the base style of the label.

In addition to supporting rich text, TTTAttributedLabel allows you to automatically detect links for URLs, addresses, phone numbers, and dates, or allow you to embed your own.

label.dataDetectorTypes = UIDataDetectorTypeAll; // Automatically detect links when the label text is subsequently changed
label.delegate = self; // Delegate methods are called when the user taps on a link (see `TTTAttributedLabelDelegate` protocol)

label.text = @"Fork me on GitHub! (https://github.com/mattt/TTTAttributedLabel/)"; // Repository URL will be automatically detected and linked

NSRange range = [label.text rangeOfString:@"me"];
[label addLinkToURL:[NSURL URLWithString:@"https://github.com/mattt/"] withRange:range]; // Embedding a custom link in a substring

Inspired by Olivier Halligon's OHAttributedLabel, borrowing some general approaches in converting between UIKit and Core Text text attributes.

Thanks to Tyler Bunnell for his fix to how touches are mapped onto their corresponding embedded links, Mark Makdad for implementing shadow color and vertical text alignment, and Daniel Tull for implementing support for highlight color.

Mattt Thompson

• https://github.com/mattt
• https://twitter.com/mattt
• [email protected]

TTTAttributedLabel is available under the MIT license. See the LICENSE file for more info.