Inherits from | |
Conforms to | |
Framework | /System/Library/Frameworks/UIKit.framework |
Availability | Available in iOS 3.2 and later. |
Declared in | UITextInput.h |
A UITextRange
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.
Classes that adopt the UITextInput protocol must create custom UITextRange
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 UITextRange
and UITextPosition
objects for communicating text-layout information. There are two reasons for using objects for text ranges rather than primitive types such as NSRange
:
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 UITextRange
subclass as well as a custom UITextPosition
subclass.
For more about Objective-C properties, see “Properties” in The Objective-C Programming Language.
A Boolean value that indicates whether the range of text represented by the receiver is zero-length. (read-only)
@property(nonatomic, readonly, getter=isEmpty) BOOL empty
UITextInput.h
The end of the range of text. (read-only)
@property(nonatomic, readonly) UITextPosition *end
Compute and store in this property the UITextPosition object representing the end of a range of text.
UITextInput.h
The start of a range of text. (read-only)
@property(nonatomic, readonly) UITextPosition *start
Compute and store in this property the UITextPosition object representing the start of a range of text.
UITextInput.h
Last updated: 2010-02-25