Programming iOS 6, 3rd Edition

Attributed Strings

Before iOS 6, controls such as UILabel and UITextView could display text only in a single font and size. If you wanted styled text — that is, text consisting of multiple style runs, with different font, size, color, and other text features in different parts of the text — you were largely out of luck. You could construct an NSAttributedString to express styled text, by dropping down to the lowest level, Core Text; but to display it in the interface you had to use a CATextLayer or have CoreText draw it, which was a lot of work. Workarounds included using a UIWebView or manipulating multiple UILabels. (For example, that’s how the TidBITS News app used to work, as shown in Figure 19-1; the bold headline and the smaller article summary are two different labels.) Editable styled text was virtually impossible to achieve.

Starting in iOS 6, however, NSAttributedString is fully integrated. With it, you can draw styled text directly, or you can hand an attributed string to any built-in interface class that understands it, including UILabel, UITextView, and UIButton.

Note

In general, interface object methods and properties that accept attributed strings stand side by side with their pre-iOS 6 equivalents; the new ones tend to have “attributed” in their name. Thus, you don’t have to use attributed strings. If a UILabel, for example, is to display text in a single font, size, color, and alignment, it might be easiest to use the pre-iOS 6 plain-old-NSString features of UILabel. ...