UITextInputTokenizer Protocol Reference

Conforms to	NSObject
Framework	/System/Library/Frameworks/UIKit.framework
Availability	Available in iOS 3.2 and later.
Declared in	UITextInput.h

Overview

An instance of a class that adopts the UITextInputTokenizer protocol is a tokenizer; a tokenizer allows the text input system to evaluate text units of different granularities. Granularities of text units are always evaluated with reference to a storage or reference direction.

Text-processing objects that conform to the UITextInput protocol must hold a reference to a tokenizer (via the tokenizer property). The UITextInputStringTokenizer class of the UIKit framework provides a default base implementation of the UITextInputTokenizer protocol. Tokenizers of this class are suitable for most western-language keyboards. Applications with different requirements may adopt the UITextInputTokenizer protocol and create their own tokenizers.

Tasks

Determining Text Positions Relative to Unit Boundaries

Computing Text Position by Unit Boundaries

Getting Ranges of Specific Text Units

Instance Methods

isPosition:atBoundary:inDirection:

Return whether a text position is at a boundary of a text unit of a specified granularity in a specified direction. (required)

- (BOOL)isPosition:(UITextPosition *)position atBoundary:(UITextGranularity)granularity inDirection:(UITextDirection)direction

Parameters

position: A text-position object that represents a location in a document.
granularity: A constant that indicates a certain granularity of text unit.
direction: A constant that indicates a direction relative to position. The constant can be of type UITextStorageDirection or UITextLayoutDirection.

Return Value

YES if the text position is at the given text-unit boundary in the given direction; NO if it is not at the boundary.

Availability

Available in iOS 3.2 and later.

Declared In

UITextInput.h

isPosition:withinTextUnit:inDirection:

Return whether a text position is within a text unit of a specified granularity in a specified direction. (required)

- (BOOL)isPosition:(UITextPosition *)position withinTextUnit:(UITextGranularity)granularity inDirection:(UITextDirection)direction

Parameters

position: A text-position object that represents a location in a document.
granularity: A constant that indicates a certain granularity of text unit.
direction: A constant that indicates a direction relative to position. The constant can be of type UITextStorageDirection or UITextLayoutDirection.

Return Value

YES if the text position is within a text unit of the specified granularity in the specified direction; otherwise, return NO. If the text position is at a boundary, return YES only if the boundary is part of the text unit in the given direction.

Availability

Available in iOS 3.2 and later.

Declared In

UITextInput.h

positionFromPosition:toBoundary:inDirection:

Return the next text position at a boundary of a text unit of the given granularity in a given direction. (required)

- (UITextPosition *)positionFromPosition:(UITextPosition *)position toBoundary:(UITextGranularity)granularity inDirection:(UITextDirection)direction

Parameters

position: A text-position object that represents a location in a document.
granularity: A constant that indicates a certain granularity of text unit.
direction: A constant that indicates a direction relative to position. The constant can be of type UITextStorageDirection or UITextLayoutDirection.

Return Value

The next boundary position of a text unit of the given granularity in the given direction, or nil if there is no such position.

Availability

Available in iOS 3.2 and later.

Declared In

UITextInput.h

rangeEnclosingPosition:withGranularity:inDirection:

Return the range for the text enclosing a text position in a text unit of a given granularity in a given direction. (required)

- (UITextRange *)rangeEnclosingPosition:(UITextPosition *)position withGranularity:(UITextGranularity)granularity inDirection:(UITextDirection)direction

Parameters

position: A text-position object that represents a location in a document.
granularity: A constant that indicates a certain granularity of text unit.
direction: A constant that indicates a direction relative to position. The constant can be of type UITextStorageDirection or UITextLayoutDirection.

Return Value

A text-range representing a text unit of the given granularity in the given direction, or nil if there is no such enclosing unit. Whether a boundary position is enclosed depends on the given direction, using the same rule as the isPosition:withinTextUnit:inDirection: method.

Discussion

In this method, return the range for the text enclosing a text position in a text unit of the given granularity, or nil if there is no such enclosing unit. If the text position is entirely enclosed within a text unit of the given granularity, it is considered enclosed. If the text position is at a text-unit boundary, it is considered enclosed only if the next position in the given direction is entirely enclosed.

Availability

Available in iOS 3.2 and later.

Declared In

UITextInput.h

Constants

UITextDirection

A direction of the text.

typedef int UITextDirection;

Discussion

This parameter is used in methods declared by the UITextInputTokenizer protocol. This general direction type subsumes constants of the UITextStorageDirection and UITextLayoutDirection types.

Availability

Available in iOS 3.2 and later.

Declared In

UITextInput.h

UITextGranularity

The granularity of a unit of text.

typedef enum {
   UITextGranularityCharacter,
   UITextGranularityWord,
   UITextGranularitySentence,
   UITextGranularityParagraph,
   UITextGranularityLine,
   UITextGranularityDocument
} UITextGranularity;