UIText object represents a range of characters in a text container; in other words, it identifies a starting index and an ending index in string backing a text-entry object.
- iOS 3.2+
- tvOS 9.0+
Classes that adopt the UITextInput protocol must create custom
UIText objects for representing ranges within the text managed by the class. The starting and ending indexes of the range are represented by UITextPosition objects. The text system uses both
UIText objects for communicating text-layout information. There are two reasons for using objects for text ranges rather than primitive types such as
Some documents contain nested elements (for example, HTML tags and embedded objects) and you need to track both absolute position and position in the visible text.
The WebKit framework, which the iPhone text system is based on, requires that text indexes and offsets be represented by objects.
If you adopt the UITextInput protocol, you must create a custom
UIText subclass as well as a custom